All kinds of problems using zap, thankfully however it seems limited to UX and error handling problems and nothing too serious. But there def seems to be 3 main areas that need improvement.
Tweaking and optimization around UX display and error handling. Should be accurate, and informative to a non-techy user.
Performance and consistence. Not sure why but using it initially, once my channels were opened everything zipped. Now it's taking a payment several seconds to go through. Sometimes I get random "unknown next peer" and other errors (related to 1)