Error parsing iTunes ID: String index out of range: -1

I'm having the exact same errors in my logs. We have "in-house" eBooks, the error doesn't seem to affect anything however as none of the books fail to push.

After an upgrade to 9.96, this still persists. I've added & removed both an in-house and external eBook to see if it would affect anything; the eBook pushed out successfully, but the warning messages still occurred.

2016-11-22 10:01:39,255 [WARN ] [duledPool-8] [EBook                    ] - Error parsing iTunes ID: String index out of range: -1
2016-11-22 10:01:40,642 [WARN ] [duledPool-8] [EBook                    ] - Error parsing iTunes ID: String index out of range: -1
2016-11-22 10:01:40,642 [WARN ] [duledPool-8] [EBook                    ] - Error parsing iTunes ID: String index out of range: -1
2016-11-22 10:02:43,438 [WARN ] [duledPool-0] [EBook                    ] - Error parsing iTunes ID: String index out of range: -1
2016-11-22 10:02:43,439 [WARN ] [duledPool-0] [EBook                    ] - Error parsing iTunes ID: String index out of range: -1
2016-11-22 10:02:44,530 [WARN ] [duledPool-0] [EBook                    ] - Error parsing iTunes ID: String index out of range: -1
2016-11-22 10:02:44,530 [WARN ] [duledPool-0] [EBook                    ] - Error parsing iTunes ID: String index out of range: -1
2016-11-22 10:03:47,060 [WARN ] [duledPool-4] [EBook                    ] - Error parsing iTunes ID: String index out of range: -1
2016-11-22 10:03:47,060 [WARN ] [duledPool-4] [EBook                    ] - Error parsing iTunes ID: String index out of range: -1
2016-11-22 10:03:47,902 [WARN ] [duledPool-4] [EBook                    ] - Error parsing iTunes ID: String index out of range: -1
2016-11-22 10:03:47,902 [WARN ] [duledPool-4] [EBook                    ] - Error parsing iTunes ID: String index out of range: -1
2016-11-22 10:04:50,524 [WARN ] [duledPool-3] [EBook                    ] - Error parsing iTunes ID: String index out of range: -1
2016-11-22 10:04:50,524 [WARN ] [duledPool-3] [EBook                    ] - Error parsing iTunes ID: String index out of range: -1
2016-11-22 10:04:51,700 [WARN ] [duledPool-3] [EBook                    ] - Error parsing iTunes ID: String index out of range: -1
2016-11-22 10:04:51,700 [WARN ] [duledPool-3] [EBook                    ] - Error parsing iTunes ID: String index out of range: -1
2016-11-22 10:05:55,215 [WARN ] [duledPool-1] [EBook                    ] - Error parsing iTunes ID: String index out of range: -1
2016-11-22 10:05:55,215 [WARN ] [duledPool-1] [EBook                    ] - Error parsing iTunes ID: String index out of range: -1
2016-11-22 10:05:56,264 [WARN ] [duledPool-1] [EBook                    ] - Error parsing iTunes ID: String index out of range: -1
2016-11-22 10:05:56,264 [WARN ] [duledPool-1] [EBook                    ] - Error parsing iTunes ID: String index out of range: -1

Still seeing this in 9.98.xxx any word on what might be causing this error and how to address it? We also have in-house eBooks (PDFs) and they install without issues.

Be nice to have the log not be cluttered with this. Thank you.

We received a reply in this thread:
https://www.jamf.com/jamf-nation/discussions/20682/error-parsing-itunes-id-string-index-out-of-range-1

Settings > Global > VPP > Content
Disable "Populate Purchased VPP Content"

The downside is you'll have to manually add newly purchased apps, but we prefer to do it this way.

Thanks @cornwella we have multiple VPP Accounts and noticed two of them had that box checked, unchecked them. Thank you!