Mobile Sidebar / Off-Canvas Menu Flashing Open After WordPress 6.9 Update

Hi,
I updated WordPress to version 6.9 today, and immediately afterward my site developed a new issue affecting mobile only.

Issue Summary

Whenever a user taps any category, subcategory, or product on mobile, the off-canvas sidebar / mobile drawer menu briefly flashes open for a split second, then closes automatically.
This did not happen before the WordPress 6.9 update.

My Setup

Hosting: SiteGround

WordPress: 6.9

Theme: WoodMart (parent) + WoodMart Child

Demo: Mega Electronics

Builder: Elementor Pro

No custom JS or recent CSS changes

All caches cleared: browser cache, SiteGround Optimizer, theme cache, and Elementor regenerated CSS

Where the Issue Happens

Only on mobile devices

Happens whenever navigating between:

Category pages

Subcategory pages

Product pages

Desktop works perfectly

What It Looks Like

The page loads normally

Then instantly the mobile menu drawer slides out for <1 second

Then snaps back closed

It looks like the drawer JS is being triggered during page load

What I Need

Confirmation if this is a compatibility bug between WordPress 6.9 and WoodMart

Any temporary workaround (CSS/JS) until an update

Or if a patch is coming from WoodMart

My category sidebar is essential for customer navigation, so this sudden flashing effect is noticeable and confusing for users.

Thank you very much!

Hello,

Please deactivate all the 3rd party plugins and activate only theme-required plugins on the site, and then check the issue. I am sure your issue will be solved. Then activate the 3rd party plugins one by one and check which plugin is creating the issue for you.

Otherwise, if the issue still exists, then keep the 3rd party plugins deactivated and share the WP login details, so I can check and give you a possible solution.

Best Regards,

I cannot deactivate plugins on the live ecommerce store, since customer traffic
and active checkout sessions are ongoing. I have active users on my store, and I do not have the ability to create a staging site.

If you still need to inspect directly, I can provide a temporary admin login, but please note:

• Do not deactivate plugins without permission

• Notify me before making any changes

Since this issue began immediately after updating to WordPress 6.9,
it appears to be a compatibility bug between the WoodMart off-canvas mobile
sidebar script and WP 6.9’s frontend changes.

Please confirm whether your dev team has a hotfix patch pending, or if this
is already a known WP 6.9 compatibility issue.

If you still need access, I will generate a limited temporary login.

Hi,

Following up with additional detail regarding the mobile off-canvas menu behavior after updating to WordPress 6.9:

Observed Behavior

On any mobile navigation event (category, subcategory, product load), the off-canvas sidebar briefly renders in its opened state, then immediately retracts.

No user tap occurs, it is triggered on initial page load.

Desktop navigation is unaffected, confirming a mobile drawer script only issue.

Testing & Isolation Steps

Without modifying plugins or structure, I applied a temporary CSS override to suppress initial off-canvas rendering. The code is below:

@media (max-width: 1024px) {
.wd-side-hidden {
transform: translateX(-100%) !important;
opacity: 0 !important;
visibility: hidden !important;
}
.wd-side-hidden.wd-opened {
transform: translateX(0) !important;
opacity: 1 !important;
visibility: visible !important;
transition: transform 0.25s ease-out, opacity 0.25s ease-out;
}
.wd-side-hidden.wd-opened-on-load {
transform: translateX(-100%) !important;
opacity: 0 !important;
visibility: hidden !important;
}
}

Result:

With this applied, the sidebar no longer flashes open on page load.

Drawer still opens normally when manually triggered.

This confirms the drawer is being programmatically forced visible for a render cycle before JS handoff closes it.

Technical Implication

Because:

no plugins were disabled, no theme core files altered, and behavior only changed once the WP 6.9 update was applied, …it strongly suggests a change in WordPress 6.9’s frontend rendering or scroll/lock arbitration is now conflicting with

WoodMart’s:

wd-opened-on-load

off-canvas transition initialization

scroll freeze / unlock handlers

Expected Next Step

Since this has been isolated as theme-level behavior, not plugin interference, kindly escalate to the dev team for a compatibility patch addressing:

off-canvas initialization firing pre-render in WP 6.9

visibility/transform state persistence prior to JS execution

A confirmation on whether a fix is planned or already in progress would be greatly appreciated.

Thank you for your time,

Hello,

To investigate this properly without affecting your live website. Please try to create a Staging platform where you can test issues, enable/disable features/plugins, thus such changes will affect the main site. Also, share the WP login details of the staging site so I can further check on your staging site and troubleshoot the issue.

The article below will help you to create it: https://www.wpbeginner.com/wp-tutorials/how-to-create-staging-environment-for-a-wordpress-site/

Best Regards,

Good morning/afternoon,

Thanks for the follow-up.

Unfortunately, my hosting plan does not include staging, so I cannot create a staging site on SiteGround without upgrading. Because of that, I cannot provide a staging login.

However, the CSS patch we added confirms the issue is isolated to the off-canvas opening animation that triggers on mobile after the WordPress 6.9 update.

This wasn’t occurring before the update, and nothing else changed on my end.

The temporary CSS code above resolved the mobile glitch, but obviously it’s just a temporary visual patch — not a core fix.

Can you please:

1. Confirm if Woodmart has a known conflict with WP 6.9 relating to mobile off-canvas / sidebar animation?

2. Provide a permanent fix or updated JS/CSS patch for the mobile drawer issue.

Because staging is not possible on my current plan, I would need a solution that I can safely apply to my live site.

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