Using modpack All the mods 3 lite. version 1.12.2
I've been crashing anytime a wooden post is placed. Was able to test it too. placed the post down and instant crashed the game.
https://gist.github.com/Katuhklizhm/7947d8ce140c12ffc6bc312a239ee5a4

sorry to tell you, but you have literally NO helpfull informations to give you any advice other than to read the contribution guidelines highlighted in yellow when you create a new issue

Im sorry I ment to put in a crash report. Should be in now @mindforger

What blocks are next to the post? One of them is doing something wrong.

it was just on dirt and I think another time it crashed it was maybe up against vanilla fence?
this would be the latest crash.
https://gist.github.com/Katuhklizhm/ac23ba9f15b3768a1b34eb987a5c4537

Are you using anything that e.g. lights up a large area nearby (anything that places invisible blocks really)?

stone torches there was also some IE lanterns nearby. not sure about any invisible blocks though.

I just remembered that i had on the miners cap (or somehthing) which emits light.

Just tried it in a creative world. put down the posts then put on the mining cap from the adventure tools mod and it crashed. Thank you!