Domain Filters not working for Firefox in Private Browsing mode

[macksimumj]

• My browser (copy from https://www.whatismybrowser.com): Firefox 120 on Windows 10
• My RES version: 5.22.17
• Am I in reddit beta (yes/no): no

What's the problem?
FilteReddit doesn't seem to work when using RES in Private Browsing. For example I have both i.imgur and gfycat filtered out but these domains are still showing in the results when searching. Double checked that these are operating normally in regular browsing mode.

Edit: I've also noticed that in regular browsing I cannot find NSFW results in search, regardless of whether nsfw:yes is included or not. Maybe there is an issue with Reddit itself?

Are there any related posts in https://github.com/honestbleeps/Reddit-Enhancement-Suite/issues or /r/RESissues?
Not that I could find.

What other browser extensions are installed?
Better History
Imagus
LastPass
Old Reddit Redirect
RES
Return YouTube Dislike
SponsorBlock for YouTube
Tampermonkey - No scripts running for reddit
uBlacklist
uBlock Origin
User-Agent Switcher and Manager