Operating system: Windows-10-10.0.17763-SP0 64 Bits
Graphics card: GeForce GTX 970/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 432.00
Broken: version: 2.83 (sub 8), branch: master, commit date: 2020-03-14 00:31, hash: rBacab7450784a
Short description of error
UDIM switch from Tiled to Single and back to Tiled will make another tile pink.
We can not reload the image, the only way that I know to fix this is by delete or remove the image data (or do Purge All) and re-open the image or manually adding UDIM Tiles on Image editor.
The expected behaviour should be whenever changed to Tiled it will reload all the other UDIM tiles. The same issue also happened in 2.82a.
Exact steps for others to reproduce the error
01. Open this attach blend file.
02. Change from Tiled to Single Image and switchback to Tiled.
[Based on the default startup or an attached .blend file (as simple as possible)]