Sync from "both ends"

This is a question/conundrum at this point, not a bug. I've raised suggestions on synchronisation before but this is a slightly different variant on that.

I was shooting a wedding yesterday. Last night, in the hotel room, I plugged an SD Card Reader into my iPhone and opened LR. I went to import all the files just for backup (planning to delete them later and backup properly). I imported a whole bunch of JPG+ARW files and then LR crashed.

Oh.

When I realised it had crashed I decided that my temporary backup solution (I don't usually work away from home) wasn't so good and pulled the SD reader out of my phone. But when I re-launched LR files kept getting added. I deleted them and they kept getting added. Eventually I found the two actions, one was importing and the other synchronising. I was able to stop the import, delete all the imported files, and that seemed to be that... apart from it kept wanting to synchronise files that no longer existed.

Back home again I did my regular import routine. Actually I had a lot of other file re-organisation to do too and when I did (as I type this) my LR Classic on my PC is showing 900 or so files being synchronised to the cloud. These aren't the wedding images but other files, mainly personal holiday photos and the like.

I went to my phone and... there's still 596 pending updates going from there too! That's files that I don't have on the phone, that don't exist on the phone.

I'm honestly not sure what's going to happen with this one.

In theory all files added to my LR on the phone go into a folder called "New Imports" that I created on my PC - so they shouldn't be interfering with the files that I've put on the PC... especially as that folder/collection is not synchronised.

I'm just unsure what's likely to happen and wonder what is *meant* to happen if you were to edit a file or files from both the phone end and from the PC end!

Because these are different files there should be no overlap. The sync from the phone to PC will, at worst, put some files on my PC that I can delete safely. The sync from my PC to my phone will move a few family photos around. No biggie.

I'm just curious what the score is with files edited at "both ends" - what's the sync precedence?

Any thoughts?