hello @Frants,
LO has some problems with the clipboard, even without clipboard manager software (which is known to make things worse),
when i tried your description in LO 7.1, win7x64, i had no fails, but instantly afterwards when i tried updating my bug-list in calc,
got a dialog box: ‘the content of the clipboard could not be pasted’, first time i see this,
you may look at tdf#130361, tdf#130147, tdf#129354, tdf#128740, tdf#128714, tdf#128663, tdf#62196,
perhaps you find a workaround, perhaps you can add some clue to the problem,
big(gst) issue: the bug shows up sporadic, thus it’s difficult for the developers to get a handle on it … 
reg.
b.