A little update:
I couldn't fix it and didn't want to go any deeper as of yet (doesn't make I might not take it apart later).
Sent a video recording showing the right shifter cannot do 11 speed as spec to both Sensah store and the sell I got it from. Here are some conclusions I got:
- Sensah directly, responded fairly fast and communication via English wasn't too bad.
- Looked at the video and said it was a problem and it needs to be replaced.
- However I did not purchase from Sensah, they were not able to provide me with after service.
Dealing with the seller:
- Communication definitely wasn't a good but did eventually get through that the right shifter was defective.
- Took a little going back and forth with them to agree to send me a replacement part
At the end, it looks like there is some after sales support for Sensah products (or I got lucky with the seller). In both cases, in order to get it processed I need to put in this $0.01 order + shipping, the seller had a free shipping option but very slow so I ended up paying $3 for faster shipping. Also in both cases they did not ask me to return the defective part (good: did not cost me to ship it, bad: how would they know this will not be a future quality issue?).