I am sure there are a lot smarter guys than me who can chime in here, but this sounds like some sort of intermittent connection or poor ground.
Have you, or some one like an electrician checked the panel for intermittents, and or loose connection?
Not to be an alarmist, but this is not normal, and could be a sign of more serious things such as something shorting or arcing.
Not sure I would wait for the power company.
Just my 2 cents
It will be my next step. I missed an opportunity when we had a complete outage overnight a couple of weeks ago. It would have been an ideal time to check all the house connections. I am thinking of cutting the seal on the meter, and taking it out to check the connections safely. I asked the power company to help me with this, but got no where, again.