After setting the grid resolution in one file and saving the file, opening a second file and changing the grid resolution applies that new grid resolution to the first file.
Environment:
Windows 10 Pro
Draw version: 7.4.5.1
How to reproduce:
create a new file
set the units to Point (Tools->Options->Draw->General->Unit of measurement)
set the grid resolution to 60 (Tools->Options->Draw->Grid->Resolution->Horizontal/Vertical)
save the file as test1.odg
copy test1.odg to test2.odg
open test2.odg
set the grid resolution to 20
save test2.odg
open test1.odg - the grid displays with a resolution of 60
open Tools->Options->Draw->Grid - the resolution is 20
close the Options dialog
toggle Snap to Grid - the grid displays with a resolution of 20
I considered filing a bug report with bugzilla, but didn’t want to have my email displayed so publicly.
Perhaps someone more involved with Draw development can file the appropriate bug report or reply with information regarding whether this is a known issue or is already resolved in a later version.