System.InvalidOperationException: There already exists

One (or more) of our graphs open with some nodes missing… The log file shows the following.

2020-01-13 18:29:57Z : System.InvalidOperationException:
2020-01-13 18:29:57Z : There already exists an AlsoKnownAs mapping for Fill Pattern Targets.
2020-01-13 18:29:57Z :
2020-01-13 18:29:57Z : System.InvalidOperationException:
2020-01-13 18:29:57Z : There already exists an AlsoKnownAs mapping for Fill Patterns.
2020-01-13 18:29:57Z :
2020-01-13 18:29:57Z : System.InvalidOperationException:
2020-01-13 18:29:57Z : There already exists an AlsoKnownAs mapping for Schedule Type.

This seems to be caused by Archi-Lab.net 2016.12.7? Can someone confirm and suggest a fix?

I am certain we have graphs that depend on Achi-Lab.