Masking turns colors muddy

Oh, and I should ask, I see that you are new to the community, but are you new to LrC editing?

Please provide screenshots to describe/demonstrate your issue, preferably using a Windows app or a third party app to take the screenshots (not a smart phone or camera).  And full screenshots, not cropped in to say just a loupe view, will want to see left and right panels, including History Panel and Histogram (some just love to have the Presets showing, gets in the way)

• How to take screenshots on Windows 11

When you reply to your discussion, please DO NOT attach those screenshots, instead use the Insert Photo Button

 The above from:

• Community How-To Guide - Tips & Best Practices

Please post your System Information as Lightroom Classic (LrC) reports it. In LrC click on Help, then System Info, then Copy. Paste that information into a reply. Please present all information from first line down to and including Plug-in Info. Info after Plug-in info can be cut out as that is just so much dead space to us non-Techs and it takes up vast amounts of scroll space making the reply less readable and less likely that others will bother with your post.

I think you need to provide more details and perhaps post a screenshot before you can expect any useful answer.