I'm one of the QA guys on the champion team here at Riot and we are all super excited that Ekko is finally going out to the PBE. We know we've caught and fixed a whole bunch of issues with him in development, but if you come across something we missed while playing him, please let us know here!
We will be combing through this thread daily to check out any issues you all come across. I'll do my best to drop in here and respond when I can, but if you don't see me (or gypsylord) around for a while its because we are trying our best to finish out these last weeks strong. If we make any drastic changes that would impact some known issues (for example: there is currently an issue where the clone from his ultimate is not displaying correctly for the other team), I'll be sure to update here.
If y'all have any design or gameplay feedback, head on over to the thread being run by Gypsylord and let him know what you think. For the sake of clarity, lets try to keep this one strictly for bugs :)
Link to design thread: http://boards.pbe.leagueoflegends.com/en/c/champions-gameplay-feedback/IwzIqm00-ekko-feedback-thread
Thanks everyone and hope you enjoy Ekko!
Edit: Ekko should be good to go in the store now! Let us know if you're still having problems
5/18 Update: We did a bunch of work on Ekko's clone from his R and we did some major rewrites on his Q as well. Specifically, this should solve Ekko's clone having his base texture when spawning in FoW and the Q disappearing before returning. However, there is currently a bug with line missiles which is causing them to sometimes pass through enemies. Working on that one now!
5/19 Update: Still working on the clone from his R. Fixed several bugs where the ult wasn't casting correctly or wouldn't heal. E range indicator should be working on very low settings (don't think the fix for casting it off screen made it in today - but its on the radar). Still fixing the Q spell to update correctly. Accidentally introduced a bug with the E where if you blink to a target that is very close to terrain, you would sometimes just apply the damage from ranged and remain where you cast from.