[gordy]

I can reproduce it without ssms by using this powershell command to set the clipboard text:

PS > scb ‘aaaa
>> bbbb
>> cccc
>> dddd’

the clipboard now contains 4 lines of text:
aaaa
bbbb
cccc
dddd

paste it into EmEditor, then highlight the block using block-selection mode (alt+click), and paste again, the text becomes:
aaaa
aaaa
aaaa
aaaa