At least for one marine creature, which I forgot its name, the answer is yes. Said creature dissolves its brain the moment it can find a place to attach and call home.

Can't think of the name atm either, but I'm pretty sure it only does so, as it would be pointless to make any further decisions after attaching itself - it simply has no means to act on anything after that... the attaching is the only thing it 'does' in it's life... after that, it's only job, and only ability, is to be. Chose the wrong spot to attach and call home? Brains wouldn't make a bit of difference (unless regretting it's one life-choice is somehow usefull during this stage of just being, being stuck on the spot).

Sea squirt. One of the simplest members of Chordata. https://en.wikipedia.org/wiki/Ascidiacea