No, not normal, but also probably not all that uncommon (sealing a piece of fabric over a tape joint is tricky.) If there is a passage for water, water will get through (and sometimes a surprising amount over time.) One other ingress point that your "fill the boat" test won't reveal are leaky one-way valves in the drains. Even with the rubber stopper plugs, some amount of water will get through.
For the leaks you ID'd, rather than glue (in which the solvent is supposed to flash off leaving a very thin layer of adhesive, hopefully bonded to both sides), I'd use a marine caulk, which is designed to fill gaps and be waterproof. In the US, Lifecaulk is a popular brand. Don't know what you have over there (drawback to Lifecaulk is that it takes a while to fully cure, like several days.)