Source Details copied with value I haven't set

[Toase-of-London]

Hi,
Just raising a big that I have noticed.
When I populate some age and history values for a building and then try to copy them to another building, the values I have set, namely:
Year of construction, earliest possible start year, latest possible start year, historical source type and historical source links and in the set of fields to be copied but so is Source Details with value "Alan Turing Institute. Computational generation test", which I haven't set.
I don't where Source Details is set so that I can clear this value, or prevent it being copied.
For examples of where this has been copied please see Elgin Avenue in Maida Vale.
Kind regards
Toase_of_London (Chris)

[Toase-of-London]

Recreation Steps:
Select building 69 Elgin Avenue, Maida Vale.
With Age & History selected click on 'Copy' and then 'Copy Selected'. Observe the list of fields includes Source Details. This is incorrect but I do not know which field to clear out to prevent it. I haven't managed to recreate this behaviour with fresh buildings so suspect it is data that was automatically generated.