I've upvoted a question but after 5 minutes I thought it wasn't such a good question after all. Now my vote is locked and I can't revoke it unless I do an edit specifically for that purpose (is that a desired effect on SE? I think not).
A question here, Vote lockdown (after some time): is it possible to revoke or soften?, explains with good arguments why the vote lock exists on answers. The reasoning there, in my opinion, does not apply to questions in any sense.
So what if we loosened the vote lock timeout on questions? Upvoting a question because it seems interesting, thinking about an answer for 5 minutes and then realizing you don't even understand the question (purely because it's more vague than it seemed at first, not because of a lack of technical competence), seems something that could happen more often.
If not possible, I at least would like to know why this vote locking is as it is on questions.