Sorry for your loss 
During 1st lockdown, I had my 3rd MC. Having been on MN a while, it seems every MC/MMC is different. From my experience, the farther along in the pregnancy I was, the longer my cycles took to regulate. It is possible that you had a small amount of retained product, hence the heavier 2nd period.
2nd MC was at 7 weeks, and natural. AF started exactly a month after the MC started, and cycles were exaclty as they were prior in terms of bleeding and a 30day cycle.
3rd I was almost 10 weeks. 1st AF was a little heavier, but normal the next month.
I wouldnt be concerned at all by irregular periods for a few months after an MC. I did a great deal of reading, and it seems the body will do everything to clear the MC and any remaining MC tissue afterwards- even if it can take a few cycles.
Best of luck and I'm sure things will settle x
My 1st MC, at 11 weeks needed medical management. I bled solidly for 2mths, then during my 1st period, it was SO heavy, almost as heavy as the MC itself. I had a small retained product that came out. It took 2 cycles for AF to return to the same as before. I had no signs of a retained product- no fever, no pain, no smell etc.