Greetings,
Getting the same issue.  I get the same issues at the following pages:
1. Mobile field serivices> work order>Work order>Items.  
2. Mobile field services> Invoices> Items
3. Mobile field services> Estimates>Items. 
Looks like anything to do with items it has a issue.  
When the error messages pops in the grid it tells me to go to a web link but its a web link to the main Method site and not a mobile log in.
John M