Should I turn off GTID to fix this error?
Short answer: Yes, you can disable GTID without risk if you're not replicating from that Server.

Long answer:

The GTID is "a unique identifier created and associated with each transaction committed on the server of origin (master)." This helps when you have some slaves; so you can always track how is your slave (which statements have replicated, from which Server, and some further information; but if you're using the server as a Standalone, shouldn't have problems, you won't use your binlogs.

You should lookup for all the cnf files, (maybe in /usr...), there should be one configuring gtid, since it's disabled by default (https://dev.mysql.com/doc/refman/5.6/en/replication-options-gtids.html#sysvar_enforce_gtid_consistency); it's important to find it so you don't have problems if someday your DB restars; otherwise it'll be ON again.

For disabling it, you'll need to restart; the link you found for disabling it without restart applies for MySQL 5.7 and further.

Finally, what it'll mean for you to disable it, you'll have your binlogs without a clear "identifier", but you'll still have your binlogs in case you need them.