Block-level sync for VeraCrypt not working post 83.4.152 update

I submitted Ticket 9861601.     The issue is that TrueCrypt encrypts files and folders into a single File  *.tc, and VeraCrypt uses similar encryption to encrypt files and folders into a single *.hc file.    To make changes to an encrypted volume, we use TrueCrypt (or VeraCrypt) to open the file (volume), then we change or update a file or files in the volume.   When done, we close the TrueCrypt or VeraCrypt volume.  [Note that TrueCrypt and VeraCrypt do not scramble the entire volume, but rather only change a subset of affected Blocks of data -- so that when small changes are made, those small set of Blocks of data are changed in an encrypted manner, but the whole file is not changed.]    In the past, all Dropbox versions, noticed when TrueCrypt or VeraCrypt volumes were "closed" (even though the date modified date did not change on the volume file)... and it would do a Block level sync to sync only the changed Blocks to Dropbox cloud, and then to all client machines files that volume was shared to.   So, it did not take much time to sync.      NOW... with the newer version of Dropbox (beginning with ver 83.4.152), Dropbox would detect the closed volume BUT was NOT actually sending changed blocks through to the dropbox cloud.   You would see the dropbox sync tray icon briefly flash, but not do a sync.   So, changed TrueCrypt and VersaCrypt volumes are not being synced.    Now it is possible to force the file modified date to change, but then Dropbox will sync the entire volume (which can be a very large file and take a very long time).    For example, changing a few files in a TrueCrypt folder that used to take 10 minutes to sync, might now take an hour and a half (90 minutes).    Please fix the newer versions of Dropbox to recognize and properly do a Block level sync on TrueCrypt and VeraCrypt volumes.   This is critical to any product that claims to have Block-level sync capabililty -- and you always used to do this.   Thank you.