generic error with stack command in siril v1.4.0-beta2

Win 10 with siril v1.4.0-beta2
I’ve tested it several times and reinstalled siril:
The first run of stack in console is fine and the second run gives a “generic error”.
After first stack command the GUI button “search sequences” is also broken.

the command is

stack r_pp_light rej 3 3 -norm=addscale -32b -out=stack

The Siril beta 1 works fine.
In beta 2 restarting siril solves the problem until the next stack command

10:40:22: Willkommen zu siril v1.4.0-beta2
10:40:22: Unterstützte Dateitypen: BMP Bilder, PIC Bilder (IRIS), Binäre PGM und PPM Bilder, RAW Bilder, FITS-CFA Bilder, Filme/Videos, SER Sequenzen, TIFF Bilder, XISF Bilder, JPG Bilder, JPEG XL Bilder, PNG Bilder, HEIF Bilder, AVIF Bilder.
10:40:22: Setting CWD (Current Working Directory) to 'E:\_Siril\M101\process'
10:40:22: Parallel processing enabled: using 32 logical processors.
10:40:22: Color management active.
10:40:22: JPEG ICC profiles supported.
10:40:22: Preparing python virtual environment: C:\Users\ASB\AppData\Local\siril\venv.
10:40:22: Checking the python module is up-to-date...
10:40:22: Installing / updating python module in the background. This may take a few seconds...
10:40:22: Warning: unable to install or update the Siril python module.
10:40:26: Running asnet version <0.88
10:40:26: Default FITS extension is set to .fit
10:40:26: Searching for scripts in: "C:\util\Siril\scripts"...
10:40:26: Loading script: Asiair_seqsubsky_1x..ssf
...
10:40:26: Gaia archive available
10:40:26: *** SIRIL NOTIFICATION ***
Note for MacOS users of beta 2: you are encouraged to download the second version of the package that fixes the multithreading issue and restores normal performance.
10:40:27: Local SPCC database repository is up-to-date!
10:40:27: Local scripts repository is up-to-date!
10:40:54: Running command: stack  <============================
10:40:54: Stacking sequence r_pp_light_
10:40:54: Processing all images in the sequence (302)
10:40:54: Stacking result will be stored as a 32-bit image
10:40:54: Computing normalization...
10:40:54: With the current memory and thread (32) limits, up to 32 thread(s) can be used for sequence normalization
10:40:54: Normalization computation time: 28.44 ms
10:40:56: Using 54139 MB memory maximum for stacking
10:40:56: We have 63 parallel blocks of size 143 (+5) for stacking.
10:40:56: Starting stacking...
10:41:28: Pixel rejection in channel #0: 0.222% - 0.563%
10:41:28: Pixel rejection in channel #1: 0.098% - 0.471%
10:41:28: Pixel rejection in channel #2: 0.168% - 0.503%
10:41:28: Rejection stacking complete. 302 images have been stacked.
10:41:28: Integration of 302 images on 302 of the sequence:
10:41:28: Pixel combination ......... average
10:41:28: Input normalization ....... additive + scaling
10:41:28: Output normalization ...... disabled
10:41:28: Pixel rejection ........... winsorized sigma clipping
10:41:28: Rejection parameters ...... low=3.000 high=3.000
10:41:28: Creating rejection maps ... no
10:41:28: Image weighting ........... disabled
10:41:28: RGB equalization .......... disabled
10:41:34: Running command: stack <============================
10:41:34: Command execution failed: generic error.
10:45:43: Running command: stack <============================
10:45:43: Command execution failed: generic error.