Since the new version was deployed to lemmy.ml which allows blocking instances I tried to block an instance.
When opening the drop down and enter the name/url of the instance (or even a part of its name) the list is then filled with a seemingly random list of instances but not the instace I searched for.
I tried in a desktop browser (Chrome on Windows) and in a mobile browser (Vivaldi Mobile, which uses Chromium as base), same behavior.
I had the same issue. I was trying to block @hardware.watch instance because it made too many posts by bot accounts from @alien.top instance. Upon a closer look, the @alien.top instance is using random bot accounts, which makes it very difficult to block. There are just way too many bot accounts from that instance.
I will wait for the issue to be resolved. At the mean time, I might just block by communities from that instance.