Strange issue with count(*) with where clause

[Frank Feingold]

I don't know that this is InnoDB related, but it's as good a place as anywhere to start.

Background:

MySQL 5.6.35 Community edition

All default MySQL settings except:

innodb_file_per_table=1
max_allowed_packet=500M
open_files_limit=10000

Basic table structure:

create table ticket (
id int(1) unsigned not null auto_increment,
department_id int(10) unsigned not null,
status_id int(10) unsigned not null)

Foreign key on department_id to a department table
Foreign key on status_id to a status table

The SQL is very simple:

select count(*) from ticket where department_id = 1 and status_id = 1

If I run this SQL multiple tickets sometimes I get the correct results and sometimes I get zero. While the data could be changing in between queries, it's really never going to go to zero.

This one really has me stumped as it's a very basic query.

Thanks in advance and sorry if this is posted in the wrong place