D90 gone crazy filenums

[reaction]

I took about 200pics today.
My pics should be up to about 5000. Anyway, I found in my SD card:

100NCD90
101NCD90
102NCD90

Wierd, why 3 folders?
Inside, my pic starts at 6pm at DSC_9949! How did it jump there?
It rolls over, then if I go by timestamp you have DSC_0001-45 from 7.23-7.35
Then DSC_0021-50 from 7.36-7.44
Then DSC_0051-2xx from 7.44-9

As you can see the range 21-45 overlaps. Yes, there are pics that I now can't put in the same folder because it went crazy.

What's the deal here? I had this once on my D80, where I swear it jumped from 2000 to 8000.

custom a7 is ON
Note it had the same lens on (70-300) until file 54 when I changed to 17-50.

[mcdesign]

Re-check all your settings reaction, have you formatted your card recently, it needs to be done after every shoot to keep it health, (like defragging your HD). Perhaps not down all your preferred setting and then reset everything back to default. Someone else might have a better idea. Also do a search on the Internet for similar problems.