I've never had this problem come up in 14 years of ingesting cards from my various Nikon, Canon, Olympus cameras. When I ingest photos, I have Photo Mechanic set the filenames to "{yr2}{mn0}{day0}_{seqn}" with a 3 digit sequence number that I reset to "001" at the beginning of each day's photos.
I've noticed that when I'm ingesting photos from a Sony A7SII or A7RII camera, the names for photos ingested start at "005" for sequence number, not "001", even though I'm resetting to 1. These are camera formatted cards, so I'm suspecting something in the filesystem on the card is fooling Photo Mechanic into thinking there are additional images that it is then unable to ingest, but that's just a wild guess.
I can rename the photos after ingesting in Photo Mechanic to start with 001 and that works. It's only when ingesting from the cards that this happens. If I ingest additional images for that day, they always start with {seqn}+4, where {seqn} is the set starting number (whether I set it, or it's been left from the last ingest). So it's incorporating that gap of 5 each time I ingest from a Sony formatted card (and I've tried using different cards in the Sony cameras).
When I look at the files on the card, I'm not seeing any additional that look to me like images, but it is the case that the structure is different from my other cameras.
Has anyone seen this and have a clue as to what is going on?
I'm running Photo Mechanic Version 5.0, build 18895 (d0ca74e) on a 2016 MacBook Pro running MacOS 10.12.6.
Thanks for any insight or info.
Linda