Following the anticipated release of the NGXu expansion and base package update, the team at PMDG discovered a corrupt output process that affected animations. As such, steps have been taken to correct the deficiency. Please see below for the complete announcement (by Robert Randazzo) including applicable installation instructions.
Late in the evening of 05FEB20, we found that we had a corrupt output process that affected animations on ALL of the 737NGXu external models. This required a reissue to correct the problem so that it wouldn’t impact you beyond the additional update cycle.
Base Package NGXu:
As of a few moments ago, you should see an update flag in Operations Center 2.0 indicating that the base package has an update available for you. That will get you up to the most current version from wherever you are. NOTE: This update is only available via micro update for the base package.
Expansion Package NGXu:
We replaced the new 600/700 installer at around 0530Z, changing the original 2.91.0121 installer for a new 2.91.0122 version. If you don’t know which version you have installed, simply do this:
1) Launch Operations Center 2.0
2) Click on AIRCRAFT UPDATES
3) Look for your PMDG 737-600/700 NGXu for Prepar3D entry.
If this entry ends in 121, then uninstall the 600/700 and redownload from your account. Then reinstall.
If this entry ends in 122, then you have the updated version and no further action is required.
We will issue a micro-update for the 600/700 later in the day if anyone cares to simply wait for that.
Sorry for the hiccup- but also thank you to a few of you who helped us confirm the issue quickly so that we could dial in a fix.
Source: PMDG forums