I just tested your sample database on my machine (10:49 AM PST). Both queries work fine for me:

If the problem is truly in a .dll file that has a different date ("ACEES.DLL" with different version numbers as you indicated), then I'm tempted to believe that perhaps your copy of this file may have been slightly corrupted during the download process and perhaps MS Access may not include the most robust error-checking to ensure an updated file is complete and correct? I'm just guessing of course. But, as a past MS Access MVP myself, I have inside knowledge that a very talented Microsoft employee on the Access team has tested the InStr function with the Current Channel and the same exact version that you reported. He found no errors.
I suppose if you really want to stay on the Current Channel, you could try converting once again to the same version. I myself am happy to stay on the slower upgrade path--I don't need or want to be on the "bleeding edge"!
If you do want to return to the Current Channel, make sure you have a solid internet connection first (wired is best, but if you use wireless hopefully you have a dual-band router that includes a signal broadcast at 5 GHz. The more common 2.4 GHz bandwidth is much more susceptible to interference (co-channel, adjacent channel and non-802.11 interference, e.g. microwave oven interference). So my WAG is that it may be possible for a critical file, such as ACEES.DLL, to be ever-so-slightly corrupted during a download process that perhaps this is the cause of all these problems. If my theory is correct, one would think the file checksum value would be altered. But does the upgrade process check for this? I don't know.