'Keyboard input' vs 'cursor copy+paste' for "repeat" (.) action

Currently using

VIM version 8.1.3741
on Ubuntu MATE (Linux 5.4.0-150-generic #167-Ubuntu)

When I copy+paste text using the system cursor,

regardless of whether that text is from another non-Vim
window, or from the text file currently in the Vim window,

if the text string being inserted is a combination of
typed-input and copy+paste,  the Vim's "." (repeat operator)
seems to ignore the copy+paste text and will only repeat
that portion of the entry which was directly-typed at the
keyboard (i.e. xyz{cut+paste_text}<return>abc )!!!

Is that behaviour controlled by a modifiable Vim parameter
which can be set to allow both inputs to be captured as
a single operation for full repeat?

Thank you,

Eric