[QGIS 3.10] QGIS crashes after download of tiles

I tested stamen_watercolour 15 for Dresden, Berlin and Heidelberg.

For Berlin I get a "area too large, choose smaller tile zoom"

For Dresden and Heidelberg, download of tiles starts but qgis exits without reporting before stitching the tiles.

I used following function to write the logs to a file easy accesible:

filename = '/tmp/qgis.log'

def write_log_message(message, tag, level):
    with open(filename, 'a') as logfile:
        logfile.write('{tag}({level}): {message}'.format(tag=tag, level=level, message=message))

QgsApplication.messageLog().messageReceived.connect(write_log_message)

Content of this external logfile:

Python warning(1): warning:/home/marcel/.local/share/QGIS/QGIS3/profiles/default/python/plugins/image_from_tms_tool/image_from_tms_algorithm.py:135: ResourceWarning:

unclosed file <_io.TextIOWrapper name='/home/marcel/projects/git/image_from_tms/input/heidelberg_tiles.csv' mode='w' encoding='UTF-8'>


traceback:  File "/home/marcel/.local/share/QGIS/QGIS3/profiles/default/python/plugins/image_from_tms_tool/image_from_tms_algorithm.py", line 135, in processAlgorithm
    grid_file, grid_file_geo = create_tiles_grid(source, zoomlevel, feedback)

Not sure if this realy is the error, as it says warning only?