After Minecraft updated to 1.18.12, a command block based addon of mine loaded in via a function command started to experience a single chunk within the structure freezing. Mobs within it stay stationary, don't react to damage (or anything), don't burn in sunlight, and command blocks within the chunk fail to function whatsoever. Kill command does not clear mobs and nothing within the chunk updates until you either leave the chunk and come back (despite it being in a ticking area) or reload the world, and the chunk is still frozen as anything new put in it or that walks into the chunk will instantly freeze. 

The only experiment turned on is "creation of custom biomes" and my addon does nothing but change numerical values in mob's json, change some recipes and trades via their json files, adds some new structures, and loads the command block area with the frozen chunk via a function command. The addon has always worked fine and does not appear to be the culprit, however the specific chunk that keeps freezing appears to work just fine in vanilla worlds. I suspect something is bugged out with either the structure or ticking area commands within the function command, causing the chunk to freeze  when either the structure is loaded into it, or the chunk becomes apart of the ticking area.

I've created new worlds with this addon about a dozen times over, and while the chunk has  loaded correctly a  couple times, most of the time it freezes. This has halted the progression of my addon, and may effect other players as well. I've included my unreleased and unfinished addon here so anyone can test for themselves. SurvivalReignited.mcpack

^{Use "/function survivalplus" to execute the function and load in the command block structure, then break through the invisible barrier blocks, into the main structure. Next spawn villagers, and punch them. They will take damage once, experience no knockback, then freeze completely.} 

Edit: Here is the full function command in question:

tickingarea add 10016 200 10000 10050 200 10050
gamerule doimmediaterespawn true
gamerule doinsomnia false
gamerule commandblockoutput false
gamerule respawnblocksexplode false
structure load SurvivalPlus 10000 200 10000
effect @a levitation 4 0 true
tp @a 10008 203 10042

Second edit: It appears that if you pre-load the chunk before using the command, everything will work fine. However if you don't, everything will freeze within that chunk.