SQL server version differences
It appears that, in the summary.txt log file, that second build number is used to indicate the service pack level.

13.0.5698.0 is SQL Server 2016 SP2 CU12.  Summary.txt replaces that bolded 0 with a 2 to indicate it's SP2.

I double checked this on a few of my instances of SQL Server, and it seems to hold true for SQL Server 2016 and 2014 consistently.  For instance, I have a SQL Server 2014 SP2 GDR instance installed locally, and Summary.txt shows the patch level as 12.2.5223.6, even though the real build number (per @@VERSION) is 12.0.5223.6.

The details of what is in Summary.txt aren't documented per se, so it's probably best to rely on SELECT @@VERSION rather than the contents of that file.