I see rim tape seems to have been the culprit. One source of slow leaks I have had is a Schrader valve core being just a small part of a turn loose in the stem. Some leaks I have had are so slow that the bubble test under water does not show anything. I also gave up on tire liners because they caused more flats than they prevented. I put Slime in my tubes to protect against small leaks, especially from thorns.