Hi Cutter. Sorry you're having this problem. I'm currently digging very deep into Tonic's code for the saving of player stats to the SQL server, and looking at the logs for this afternoon. It's all very strange - you seem to be a 'special case', but I haven't yet worked out why.
This post is just to tell you that I am looking, and you've not gone unheard!
In a nutshell, the other players that I have studied during the same session as you, all appear to be logging stats every ten minutes or so, plus any other time they've manually synced, plus the times they've been to the ATM and altered their money status (bank vs hand).
You, on the other hand, only appear to have synced twice (whether automatically or manually I can't see, but I would have expected several more, in the time you were showing as online). I can see where you've logged in and got your cash from the DB (18:49), been to the boatshop and pulled out your boat (18:53, three queries to find, fetch and then mark your boat as active in the world), and then nothing until 19:38 where a DB write happens, in which you have no cash in hand, and 302997 in the bank. That's 40 minutes or so where there were no auto-updates for you - I would've expected at least three or four in that time. Next, there is a fetch from the DB (presumably that's when you re-logged) at 19:48 and a final write-out at 19:56 (just after your post above) where you saved 309596 to the bank (again, nothing in hand).
I haven't yet checked to see if there was a successful raid on the Treasury during that period (this might have reduced your cash-at-bank by a certain amount) - but even so, there is clearly a problem with the ten-minutely auto-sync happening for you, and possibly even the manual one as well (I think the two write-syncs listed above are caused by you visiting/updating the cashpoint, rather than anything else, but it's hard to be 100% sure, because Tonic's code doesn't differentiate the cause, in these logs).
You will get your money back, but I'm more worried as to the underlying cause of this. Why should the auto-updates and manual syncs be failing for you, but working perfectly fine for other people? I'm struggling to find the 'missing link'. Anything unusual or odd about your Arma3 installation or your networking arrangements that might help us to know? If I can find the root cause, I can try to fix it so that it doesn't happen again for you or others (and a few report similar issues, but the majority are fine, which is most odd).
Let me know if you think of anything. Meantime, I've added in the missing cash, but fully expect this to re-occur, until we find out the true cause. Sorry for the inconvenience.