Liner was installed 3 months ago customer says has leaked ever since. Bucket test shows 1/4" water loss. Plumbing test good and have spent two hours under water dye testing. Need help ?

Use a leaktrac to locate leak, dye test to confirm. Many leaks in liner installs are from the bottom of the steps because liner was not pulled in enough when water was added and the liner has pulled down on one or more screws.

you said bucket test showed 1/4 inch loss, what did the pool side show? was the loss equal in the bucket and the pool??? if so this leak, you are just chasing a ghost.