odd small pixel tiles seen in hdf5 image after animation stops

[kswang1029]

Describe the bug
odd small pixel tiles seen in hdf5 image after animation stops

Screen.Recording.2022-05-11.at.15.50.40.mov

To Reproduce
Steps to reproduce the behavior:

1. load an hdf5 cube
2. start and stop animation playback repeatedly
3. observe the image quality, especially near the NaN edges.

Expected behavior
No such image defect after animation playback stopped.

Platform info (please complete the following information):

• OS [e.g. macOS Monterey]: macOS Monterey
• Browser [e.g. chrome, safari, electron app]: electron app
• Browser version [e.g. 22]: 101
• Backend branch [e.g. dev, v3b2 release]: v3b3 test electron app
• Frontend branch [e.g. dev, v3b2 release]: v3b3 test electron app

also seen in the v3b3 AppImage packages.
also seen in dev
also seen in v3b2 macOS electron app

[kswang1029]

lower priority for v3-final release.

[YuHsuan-Hwang]

Perhaps this could be a backend issue. If we hover the pixels on the edges, we also see the cursor values are not NaN. From the protobuf log, we can see that the values are from the backend.

(left: M17_SWex.fits, right: M17_SWex.hdf5)

(SPATIAL_PROFILE_DATA messages, the first one is M17_SWex.fits and the second one is M17_SWex.hdf5)