El Capitan Finder fails to update changes on NAS (SMB network share)

I've got a trusty QNAP TS-469 Pro that I've had through many versions of Mac OS X. It has worked reliably sharing up several SMB/CIFS shares to my 2012 Macbook Air 13" as I upgraded over time from Mountain Lion through Yosemite.

Immediately after upgrading this Macbook Air to El Capitan, I noticed that the Finder frequently fails to update the file or folder listings within folders on the QNAP's network shares if they are changed using a different computer. For instance, if I am connected to a share on the NAS, and someone else in the family puts a file up there, I can't see it, not through the Finder and not through Terminal either. We all use one of two admin-level user accounts on the NAS, so it is PROBABLY not a permissions issue--both user accounts can see and change everything on the NAS.

I have to eject the network share drive and reconnect to get the new listings and see the file.

Another example: if there is a file that I currently see and someone else deletes it, I still see the file. When I double-click on it, my Mac tells me the file no longer exists and fails to update the Finder to indicate this. (The file still remains there until I use the eject/reconnect workaround.)

This failure to update file/folder listings happens all the time and always and only with my El Capitan system. Non-El Capitan Macs (and of course non-Macs like our LINUX box and our Windows 10 PC) see the listing changes properly.

This problem exists whether or not I am logged in as me or as a guest account (on the NAS) and also happened in both cases where I did an in-place upgrade from Yosemite to El Capitan and then wiped the drive and did a clean install of El Capitan (same Macbook Air at different times--I thought wiping the drive would fix this issue I am describing). Also, the problem was present in El Capitan 10.11.0 and is still present in 10.11.1.

It is pretty annoying, but the workaround does always work.

Anybody else seeing this issue?

QNAP has not released any firmware updates that may have caused this, and I have the latest update they made (installed prior to the upgrade to El Capitan). I do not think it is a problem on their side given that other brands of NAS seem to be having trouble with El Capitan's Finder too. Apple probably changed the way Finder caches the file/folder listings.

Thanks in advance for any help you may provide!