Around any cab over windows. Below any cab over marker lights. I had to
re-caulk mine a couple times. The metal edging can be a water trap too. I have a tape seal on all of mine. Check the nose of the cab over where it connects to the TC roof. Does everything look clean and well sealed up there. I had to scrape off the old and apply new sealant to mine where the aluminum rooftop meets the filon of the nose.
Give it a good inspection. Anything that doesn't look right as my rule, probably isn't right.
Good luck.