Stacking keeps failing because siril fails to load an image

I have been using Siril and Sirlic for years now and lately I keep having stacks fail with the following error:
log: FITS error: Error reading data buffer from file:
log: FITS error: r_image_group_00439.fit
log: FITS error: Error reading elements 1 thru 313099776 from image (ffgcle).
log: Could not load image 438 from sequence r_image_group_
log: Normalization failed. Check image 439 first.

When checking the image, it’s there… No idea what’s going on