The Trouble with MODIS

The trouble
In my GEO and LEO scripts I use delayed composite generation setting generate=False for speed. The issue is seen with Aqua and Terra MODIS data from EUMETCast. Using generate=False I get ugly big pink stains in images with composite 'true_color_thin'. No problem with other composites (so far) and with generate=True. I suspect that different possible resolutions in channels produce this bug.

To Reproduce
I made a minimum script including data that reproduces the problem generating four images. The wetransfer link is:

https://we.tl/t-cIufngDaCJ

(issue0731.zip, 168MB, the link is active one week from now)

Expected behavior
I expect that generate=False makes the same fine 'true_color_thin' image as generate=True (that I have used in the past).

Actual results
No obvious difference is seen in normal text output. No special debug output has been generated.

Screenshots
Reduced size output images can be found on the google list:

https://groups.google.com/g/pytroll/c/BejWK4jiEc4

Environment Info:

• GNU/Linux
• satpy 0.37.1 pyhd8ed1ab_0 conda-forge
• pyresample 1.25.1 py39h1832856_0 conda-forge

Additional context
I'm currently updating my PyTROLL/Satpy Kit of scripts for EUMETCast. Making many composites I want to go the delayed composite generation route as far as possible. Up to now I only found that GEO composites with DAY/NIG background files do not work this way.

Start with the minimum reproduction script and data in issue0731.zip, then compare the true_color_thin composite with generate=False and generate=True for the Aqua and Terra MODIS inputs. Trace the delayed composite path and channel resolution handling; done means generate=False produces the same artifact-free image as generate=True.