[Koha] koha index issue

[Viliam Polonec]

Hello


koha version 19.11.19

We have bibliographic records with identificator from another system in 
field 035. This field is indexed as Other-control-number. This 
identifcators contains numbers and letters

When I try to search in koha "as00g2oe", koha returns 30 records, only 
one has identificator "as00g2oe" in 035. Other records contains only 
"as00g2o" (without e at the end). It looks like oe is equal with e

koha returns records with identificators: as00g2o1, 
as00g2o2,...,as00g2oe,as00g2of, ...as00g2oz


When I try to search "as00g2fe", koha returns only one record. But 
searching "as00g2f" returns 30 records and every record contains "as00g2f".

The issue is only with oe at the end of string


What's wrong with koha index?


thanks


Viliam