A Veracrypt file isn't synced correctly

hallo! thnx for helping me it is very important for me to have my personal files on the cloud, the best there is dropbox so....

1) i always use dropbox desktop app to make things. Not sure what u mean here when i first installed dropbox then i put into the local folder of my PC a veracrypt encrypted file (called PerW). then it started syncing. it finished (after many hours cause it was 9GB) and for many time i think until recently some months now it worked.

2) The second screenshot is of the file after i downloaded it from your website YES! just for testing purposes (open, mounted)

3) Now veracrypt is working with dropbox with this way: When i locally open (temporarilly decrypt) the veracrypt file (which i repeat its encrypted by me) i mount it (create) a virtual drive that contains everything my veracrypt file contains so that i can process it. after processing it, for example make a change in a word document, or a txt etc nothing yet happens with dropbox. WHEN i dismount (close the virtual drive, encypt it again) the veracrypt file of mine THEN and ONLY THEN dropbox uses deltasync to sync the changes made to that huge file of mine of 9GB. so it takes a little time to finish (it doesnt reupload 9 GB i mean)

so what u see in screenshot is on the left side a W:\ drive (this is the local unencypted virtual drive) and on the right side the veracrypt file i downoloaded from internet to my desktop to open it to see whats in it. i mounted it on U:\ drive for example, could be any letter. and the files inside where much less than my local veracrypt file. then i had a heart attack so i wrote here to find out why and how to prevent this from happening again

all started when i noticed that when i closed (dismount) a veracypt file the dropbox did NOT sync anything (the icon on taskbar was like nothing happens, didnt have the sync icon next to it)

thats all i hope i helped if u need something else tell me to write for you. right now the only thing i am thinking to do is to reupload the whole file (9GB), but thats the whole volume, files inside are less until they reach 9GB (which is maximum set filesize for veracrypt file, this is how veracrypt works)

also i need to say that i have done this test to far past time and it worked ok. the file that i have uploaded is called PerW (without any extention indicating its a veracrypt file , doesnt need one i have deleted it for security reasons)

..............something last when i tried to download the file from dropbox with chrome or firefox both stopped the download and i couldnt resume. i used jdownloader to manage to download it.. maybe something has to do with download banwidth of dropbox or something per file?

thank you!