I had a similar situation with an SAP Ariba web page. I couldn't use the read stage with Get Check State because it always showed "False" as well. I suggest you spy at least the first three or 4 rows of the checkboxes with a certain spy mode, such as...
I recently learned that you can also spy one field of the table, then in your 'Read' stage for that 'Element' choose the Data option 'Get Table'. It brings the table (and possibly some blank columns and rows) into a collection. I happened to use th...