Date in column header won't work in formula

I've built an amortization table and have dates as column headers.
1/1/2019, 2/1/2019, 3/1/2019,...

In another table I have Start Date and End Date columns. I've built a formula that essentially says, =IF(AND(1/1/2019 is > Start Date, 1/1/2019 < End Date),"TRUE", "")

So if it's between the start and end date I want a "TRUE" result.

This formula works fine when I have my data in just a range. (as you'll see in the file).
The second I turned that range into a table the formula gave me a false reading (because the dates in the column headers are now acting as TEXT and not DATES, despite me changing the format to date).

How can I fix this or workaround it?

See file attachment.