I think a theme update has changed how the variation special price shows. Before the variation price showed the original lower and higher price crossed out with the sale lower and higher price below. Now it only shows the sale lower and higher price on the choose an option variation. Is this a change that there is an option for? I hope that makes sense.
Please see attachments, the variable products that have a sale price used to have the original price crossed out above the sale price as in variation-special2.jpg (Please note I have just added in the text to show example.)
Now it is showing like variation-special.jpg, only the sale price is shown.
Could you please check how it works with some default WordPress themes like TwentyTwenty or WooCommerce Storefront to understand is it our theme issue or not? Send us a screenshot so we can compare it with WoodMart and a link where we can check it.