Merc 2.5ltr 2003 with Auto Oil drama.

[Old boy]

Greetings from down under!
I have owned my Merc 2.5ltr EFI 150hp Limited Edition (Retro) 25" outboard, since brand new in the carton.
A few months ago whilst underway, the Oil alarm was sounded. I discovered the cap on the reserve oil bottle under the cowl had popped up about 2-3mm (1/8") and was leaking oil. I retightened it by hand, started the motor and within five minutes the alarm sounded again. I removed the cowl to find the cap had popped up again. I retightened it by hand for the second time, then I found the thread of the reserve bottle was actually stripped (threaded).
I located a used bottle, checking the thread condition of the bottle first, fitted it to my motor... problem solved! Yeah

After about 6 trouble free outings in my boat and say 6 engine hours later, the alarm sounded again. I immediately stopped the motor checked the oil level of the primary oil bottle located in the boat, the primary bottle was at least half full. However, I noticed two pronounced white stress marks on the front face of the primary oil bottle, plus it was very puffed up.
Then, I removed the cowl and checked the cap of the replacement reserve oil bottle. The thread of that bottle was stripped, exactly the same as my original reserve bottle.
Is there a possibility of something causing over pressurization of the Auto Oil System?
I'm at a total loss of what steps to take next, all suggestions will be appreciated.

Thank you in advance,
Guy.

[bullet123]

Most of us remove the oiling system and premix. Probably not a bunch of knowledge about oil systems on this site. Try Bass Boat Central. They deal with many more stock motors on that site.