Steps to Reproduce:
1) Create a world in 1.19.4 with experimental datapacks on
2) Run /locate desert_pyramid
3) Place a load of blocks in the chunks where the suspicious sand naturally generates in
4) Convert world into 23w12a
5) Chunks reset here
Starting from Step 3:
4) Pick block - with NBT - the naturally generated suspicious sand
5) Keep it in your inventory
6) Convert world into 23w12a
7) Game crashes
Relates to MC-207077