Mansion generates 1 block too low compared to before and now sometimes causes a weird waterlogged entrance or the entrance being a block below terrain.
this has been the case since 1.19.
in 1.18.2 it was good

Here is some examples: 

seed: 238193834 
/tp 11 63 32
in 1.19+: half waterlogged entrance and 1 block below terrain
in 1.18.2: is right on top of terrain

seed: 9137659977
/tp 49 64 -5
in 1.19+: completely waterlogged entrance
in 1.18.2: is right on top of the water

this is also very noticeable if you /place a mansion on perfectly flat area, it will be 1 block below terrain
you can try this in a superflat world very easily
make sure its a superflat world with y60+ as ground level otherwise mansion can not be placed
heres a superflat preset that works minecraft:bedrock,125*minecraft:dirt,minecraft:grass_block;minecraft:plains
then do /place structure minecraft:mansion
you will see its dug 1 block into terrain