In CSV import a leading ' apostrophe is stripped if the field content continues with a numeric value, e.g. '3
This is related to
but the LibreOffice implementation already does not remove the apostrophe anymore from textual values, only from otherwise numeric values.
See test case https://issues.apache.org/ooo/attachment.cgi?id=37545
Eike Rathke committed a patch related to this issue.
It has been pushed to "master":
resolved fdo#48731 in CSV import do not strip leading apostrophe