The developer, Alessandro Pignotti, did not explicitly advertise "Removing cheats" in the changelog. Instead, the patch was part of a massive core overhaul.
Here is the technical truth: Lemuroid relies on Snes9x for SNES, PCSX ReARMed for PS1, and mGBA for GBA. As of early-to-mid 2024, the developer switched to newer, more accurate versions of these cores to fix save-state corruption and audio lag. lemuroid cheats patched
Unfortunately, the newer cores handle memory differently. The cheat engine that worked on the old cores is incompatible with the new ones. and loading that file into Lemuroid.
Specifically, the patch did the following: PCSX ReARMed for PS1
RetroArch is the engine underneath Lemuroid. While its interface is less polished, its cheat system remains fully functional and unpatched. You can even use the exact same .cht files. It takes an hour to configure, but once set up, it is more powerful than Lemuroid ever was.
You mentioned "patched" content. This is where most users run into trouble.
.gba (or relevant extension) file, and loading that file into Lemuroid.