Admin comment reply appears as “anonymous”

Hi, thank you for your nice app I use & promote for years.
recent updates (5.0.2 & 5.0.3) brought a strange issue : when as admin I try to reply to a comment, It creates an empty message with author “anonymous”.
I checked with 4.x.x on an old staging I upgraded to WP 5.6.2 : no issue.
I tried on another site on a different hosting, same issue.
How can I help debugging ?

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