Invalid byte sequence errors on DB restore

[Samuel Smith <pgsql@xxxxxxxxxx>]

My current DB backup routine is just to call pg_dump and pipe to gzip. 
We recently started to get a failure to restore (which is basically just 
using psql -f on the pg_dump file) with the following errors:

invalid byte sequence for encoding "UTF8": 0xa0
 and
invalid byte sequence for encoding "UTF8": 0xd7 0x20


This is on a pg 9.2.24 instance. Any tips to troubleshoot?

Regards,
Samuel Smith