Okay thank you, after providing all as parameter to the TEST command, it downloaded and checked all blocks:
Summary
duplicati-i32991eab13a04eb29f13bf810d9bf84c.dindex.zip: 1 errors
Extra: nWCk5LXtVbpJfU3oHK+Qaf0tZkCR1U71mLBxVNR7YPg=
duplicati-iee29f33c698348ff99fe5d361c55d22c.dindex.zip: 1 errors
Extra: 5GsXqom6FcVOhRaA4JXs9M5/eSnWfliYLMKTfOlqU+0=
duplicati-id47670d5c1e74e8fbee31b62b5c3d87a.dindex.zip: 2 errors
Extra: ELLWpZNLk05pLAj7252gwrBr498jJoZnaSjo1opSsSs=
Extra: ug/SSt/fkhKrNjT+Vr+mwwCAGypuATSmmoavmvS5Nj0=
duplicati-i7e229d27fb344470a3866321a4d16b90.dindex.zip: 423 errors
Extra: +3+w7NRTAwetxlyqms47cdmPRXzx5XR+yoDeNwx6ZKY=
Extra: +3OtWm8FUl0SYiSJf4gtwdfhMS9aJ51BNzbq07EyBQs=
Extra: +HcjS7ybedw7d1TnH4WQDtVj42hE47phq8paC0K1Rpw=
Extra: +Hkvsj/+cD5UR5LoOuiUJKe5n4xD1SFRe9pmZ8kzi6U=
Extra: +IQYR/GoRJ1Rb3RAV+qzM1cRFieG7cJS9hLTw43B7CU=
Extra: +M0iKGCPG5U5zfffeOhQzolETjvBXryA9jrd21PpE7s=
Extra: +lVKUmpylAKrVj+dXfDp0tJFx5gcAo/2bUT09K/XESE=
Extra: +rMTbXIBN0OMaFJcN5v1AdSlYfRZKGi4Fq+MBL8H/mY=
Extra: +zB/plR+nDc3Yid5KbHzQEPV4Al2D309vMHwqmSJ4C0=
Extra: /5uDoG544HxP6mWj9K4OPrRjz6ahY8uJJ4Nms6yD+bg=
… and 413 more
duplicati-i1603b9340b2f4bf49add50a55ef6fd9b.dindex.zip: 1 errors
Extra: 8EMDYQ0V3Npa3+pJpn7ry0oDcvTWlsbN1s9SygqCY84=
duplicati-i8c1d6670677c4f9cbbaf246b6eb44c98.dindex.zip: 1 errors
Extra: 4SWPGr1EjUsIxYJBnDdVUfws4nArO0cjXkWAPkxumv8=
duplicati-i8f5532119bb14c1bbee92464ac5ab999.dindex.zip: 2 errors
Extra: YUJSU9Yqj0eHZ1mvojY4EySZ9GJ+RFXuGBCV1E5GtFg=
Extra: zYzRoD7xD+Te31unpP/7/0PGPBl3xfoIJM0aiYKE1Os=
duplicati-if62dafaed8b8487eb9359d01a6208393.dindex.zip: 1 errors
Extra: DJlg65r3FidiBzcTKE+WgSGKtIdSERu2b3KBAcY9h08=
duplicati-b5120a18a6b5e4a9f90a663f55335ba68.dblock.zip: 423 errors
Extra: +3+w7NRTAwetxlyqms47cdmPRXzx5XR+yoDeNwx6ZKY=
Extra: +3OtWm8FUl0SYiSJf4gtwdfhMS9aJ51BNzbq07EyBQs=
Extra: +HcjS7ybedw7d1TnH4WQDtVj42hE47phq8paC0K1Rpw=
Extra: +Hkvsj/+cD5UR5LoOuiUJKe5n4xD1SFRe9pmZ8kzi6U=
Extra: +IQYR/GoRJ1Rb3RAV+qzM1cRFieG7cJS9hLTw43B7CU=
Extra: +M0iKGCPG5U5zfffeOhQzolETjvBXryA9jrd21PpE7s=
Extra: +lVKUmpylAKrVj+dXfDp0tJFx5gcAo/2bUT09K/XESE=
Extra: +rMTbXIBN0OMaFJcN5v1AdSlYfRZKGi4Fq+MBL8H/mY=
Extra: +zB/plR+nDc3Yid5KbHzQEPV4Al2D309vMHwqmSJ4C0=
Extra: /5uDoG544HxP6mWj9K4OPrRjz6ahY8uJJ4Nms6yD+bg=
… and 413 more
duplicati-b10535f47191444ee920daa169a21b1b0.dblock.zip: 1 errors
Extra: 8EMDYQ0V3Npa3+pJpn7ry0oDcvTWlsbN1s9SygqCY84=
duplicati-bcfb756184e76499bac81a120dacb6c1d.dblock.zip: 2 errors
Extra: ELLWpZNLk05pLAj7252gwrBr498jJoZnaSjo1opSsSs=
Extra: ug/SSt/fkhKrNjT+Vr+mwwCAGypuATSmmoavmvS5Nj0=
duplicati-b6061c95a7d134b4b9442d1dbe78c3997.dblock.zip: 1 errors
Extra: 5GsXqom6FcVOhRaA4JXs9M5/eSnWfliYLMKTfOlqU+0=
duplicati-b6a5e868b72294067918ca3d0fd2497a2.dblock.zip: 1 errors
Extra: 4SWPGr1EjUsIxYJBnDdVUfws4nArO0cjXkWAPkxumv8=
duplicati-bfe584620fd1a450db7388dbdc35bf95a.dblock.zip: 2 errors
Extra: YUJSU9Yqj0eHZ1mvojY4EySZ9GJ+RFXuGBCV1E5GtFg=
Extra: zYzRoD7xD+Te31unpP/7/0PGPBl3xfoIJM0aiYKE1Os=
duplicati-b29018e64734d480c83652efba4e0d2b0.dblock.zip: 1 errors
Extra: nWCk5LXtVbpJfU3oHK+Qaf0tZkCR1U71mLBxVNR7YPg=
duplicati-b268b6dbbd11a4f08994e5c59156c6963.dblock.zip: 1 errors
Extra: DJlg65r3FidiBzcTKE+WgSGKtIdSERu2b3KBAcY9h08=
It gives several hundred errors but according to your explanation, I learned this is not critical. I will still need to again deep-dive into those parameters to get a better understanding how they work in which siutation.
Big thanks so far!