I forgot about it
.
Like 15 min ago I installed Chrome (before I tested in Chromium), logged in with my fake account, went to this thread, put the cursor in the reply box, and put my phone on the space bar. Then I went to do some other bussiness, and 10 min later the focus was still in the box, producing lots of spaces. So...
, cannot replicate the problem.
I've given you now temporary "supporter" status, to see if this changes anything. If so, then the problem is indeed with the ads. I doubt this though, I think it might be a Chrome plugin or something else in your specific Chrome setup which causes this.
But let's see how it goes for a few days, then we know more.