timestamp error when registering in comet/asteroid mode

I tried using Siril to process C2022. The star registration worked fine, but when trying to do asteroid registration, after trying to create the box containing C2022 and clicking ‘pick object in #1’, I got the error that there is no timestamp, and Siril cannot use the image.

However, this is a sequence of FITS created and registered in Siril (v 1.0.6, on Ubuntu). The image info shows a timestamp, and as far as I know the timestamp has to be filled by Siril on creation of the FITS image as it is a compulsory field.

Can anyone tell me how to get past this, or can give me a hint of what to try to better know what is going wrong?

Thanks for your help!