@crinrictThanks for the reply! I saw that a similar issue for this was already posted, and as mentioned backfloating with a non-mermaid Sim does not show the same characteristics. My personal interpretation is that this bug might have been fixed for normal Sims but still exists for the mermaid specific "Sleep In Water" interaction.
Comparing the tunings of both interactions shows that backfloating in water has some different values than the mermaid "Sleep In Water" interaction, such as the "waypoint_override_agent_radius" for backfloating is 0.45 while for mermaid's sleep it is set to 0.5, and that backfloating is set to clear it's locomotion mask while that line of code is absent for the mermaid sleep. Putting those into the mermaid sleep interaction tuning via a script mod does make mermaids able to interact with lava rocks after sleeping in the ocean, but I will not pretend that this is all there is to it, just my personal observations to provide some pointers of where the bug might be. Whether these are helpful or not is not my place to say, I just hope they are. :P
As for it happening on other lots, to clarify I removed all mods and cleared my caches, then went to Newcrest and had a mermaid sleep in the pool and interact with things. Tho before, while the bug was active, I remember mermaids having some routing issues with toilets, after testing in regards to that, they were able to use it no matter which composition of furniture or walls I placed around the toilet.
Thus as of now I can only say that I am able to reliably replicate the bug with lava rocks. It is not restricted to the Key Point lot in Sulani, but at least as far as I have tested I wasn't able to find any other objects affected by the issue at hand.
