I've posted articles about dfuse in the past.
Dfuse problem, B-L072Z-LRWAN1
The answer is v3.0.6 is said to have been modified.
"I had this same issue and ST gave me a Pre-Release version of the DFUse(V3.0.6) Software today and the problem has been fixed."
In ST, v3.0.5 is available for download.
Can not you pass me the v3.0.6 version?