Makita DUR369L obstruction light

[River]

I have a makita DUR369L grass trimmer, the little electric brush cutter. I’ve had it for a while, though it’s not often used, as I have two bulkier ones that run on fuel. I’ve recently run out of fuel so cracked out the electric, just for some minor trimming, nothing major. I’d never had a problem with it before, but now, occasionally when I release the trigger, not every time mind, the obstruction light will come on blinking green. There’s nothing trapped in the head, it turns fine. Sometimes I’ll leave it for half an hour and it will work, sometimes a few trigger taps and it works, sometimes I hit reverse, and it works fine after that. It’s very annoying because I’ll release the trigger to move locations and suddenly it stops working entirely. Any help would be much appreciated. 

[Eric - TIA]

Sounds like an electronic problem but I have no idea of where to start except to call Makta support 1 (800) 462-5482.