Hicap mag fixes?

[Bad_Intel]

I have a few Dboys M4 mags that I took to a skirmish yesterday. I found at different times nearly all had winding issues. On arrival one stopped working completely, another unwound itself twice as I put it into gun and the other went loose with no wind after it had been fine all day...

Are these common issues? Is there a maintenance proceedure for mags?

I was able to unjam one when I bought them (2nd hand), so understand a bit of inner system, but do need advice on either fixing these or knowing when to bin them.