Hello Guishop. I have the same problem. I have to change the dive number manually after every dive. Were you able to find a solution?
Okay I have a mk2i and when I first used it, I just set the dive counter to 100 as I didn’t have my log book handy and I wanted to play with my new toy. Now that I have my log book I would like to sync the dive counter to match my paper log book, I have manually edited all the dives to have the correct number, but each time I start a new dive the counter continues off from the last dive number that the watch used and not from the dive number in my Garmin log file.. how do I change the dive number in the watch so that it will have the same numbers as my paper dive log book? Searched the web but didn’t find anything, have played with Garmin dive, Garmin connect and Garmin iqconnect, but cannot find the dive number or modify it? I actually read the user manual (very rare for me!) but it didn’t touch on this subject.. would really welcome any help, it’s a minor issue, but very annoying to have 2 dive log systems that don’t match!!
I had the same issue with my new mk2s. I finally figured out that I could go into the Garmin Dive iOS app and manually add a log for my last dive and then edit the dive number to be the correct value and this seems to have updated the Cumulative Dive Number under Settings - User Settings, to the number that I set in that dive. Now I needed to increase the number. I have no idea if you can decrease it.
I also noticed that I could set the dive time to 00:00 so that it did not change the Cumulative Total Dive Time which was already correct.
Interestingly I also discovered that deleting that one Dive Log entry reset the Cumulative Dive Number to 0. So, I think that your first Dive Log can be used to set the number correctly.