NumberFormat incorrect warning - requires a delimiter every three digits

[dylan-chong]

NumberFormat: Number 2017, requires a delimiter every three digits (eg: 1,000.00 or 1.000,00).

I get the above incorrect warning with the sentence In January 2017, it was announced

[nicolaiskogheim]

Another case: links like this one:

https://superuser.com/questions/229743

NumberFormat: Number 229743 requires a delimiter every three digits (eg: 1,000.00 or 1.000,00).

[nicolaiskogheim]

Related: #728

Edit: On closer inspection, maybe not.

[dylan-chong]

Another case: Version: 1.2.3 gives this format warning too!

[edwardwoodward]

In addition to the above, I have the phrase "Ignore 4 digit integers (2015, 1998)" inside a table in asciidoc format. With ignore_years set to false, neither 4-digit number is flagged. If I copy the same phrase to another place in the document (not a table), both numbers are flagged.
If I set ignore_years to true, the 2015 in the table is flagged (but the 1998 is not and neither are the 4-digit numbers outside the table).