Problem: The upshift lever on my Ergo shifter sticks. It's still functional, but it's not working the way it's supposed to. The issue may have just happened today, or it may have happened when I took the shifter to a plastic welder who tried to fix the upshift lever that I broke a few weeks ago (I've been using a downtube shifter ever since).

Here's the situation: A few weeks ago I stupidly snapped the upshift lever on my left shifter. I took it to a guy who does plastic welding, and he should have known better, but he melted goop onto each butt end of the two broken pieces and attempted to get them to stay together. They didn't, as I discovered the first time I tried to shift.

So I ordered a replacement upshift lever. It came today. I immediately went to my shed and disassembled the shifter as per video instructions (https://www.youtube.com/watch?v=8Y5Sn_Jnkus), replaced the broken lever with the new one, and put it all back together. But now the upshift lever sticks when I shift up to the big ring.

Here's a quick video depicting the issue (click on image):



Is there a spring loose or needing replacing? Is it possible that I didn't tighten the spring enough as shown at 3:48 of the following instructional video?