oil reservour fill problem 2004 merc XLSWB

[Proline06460]

I have a 2004 carbed Merc XLSWB. I am having intermittent problems with the reservoir on the tank automatically filling up with oil from the reservoir. The oil was not filling in the spring. A new fill tube was put on in the spring. When the mechanic took off the cap and blead the system the oil started to fill in the reservoir and we thought that it was fixed. The engine was used once and then the engine was left up for a couple weeks. No oil was leaked and then the oil alarm started to sound when I started the engine to charge the batteries. I then proceeded to make the oil reservoir half full and then the engine was left to run for a minute and the oil filled all the way to the top on its own as it should. Is this a sign of problems with the oil pump? Or is this just a crazy coincidence. Any insight would be greatly appreciated.