Google sync duplicating edited calendar entries

This is a little bit of a bizzare issue that hopefully someone on here has experienced and knows a fix.

I have several google calendars that all get sync'd on my BB calendar under one email address using google sync. The calendar I share with my wife works seamlessly. Entries are added, edited or deleted and they show up correctly both on PC or BB.

However, the issue I am having is with a my work calendar which is managed by a coworker. Again, entries are added or deleted no problem but when she makes any changes to an existing entry, my BB calendar will show 2 entries; the original entry and the newly edited entry. Very strange. If I go ahead and delete the older entry off my BB calendar, it will delete the edited entry online which causes problems for everybody else sharing the calendar (about 15 people). If I log out of google sync and sign-in again, the entries show up correctly once again until the next time she makes an edit and my BB syncs again.

The edits usually just comprise of a tittle change and the time slot usually remains the same so my BB always shows a conflict when 2 entries show up.

Anybody else experienced this before? I've checked that she only one email address linked to it which is my gmail but on my phone all my entries are set to my yahoo address. Not sure if that matters.

Thanks.