Items erroneously being added to invoice/estimate as zero dollars

[Nancy]

Has anyone had issues with mobile users adding an item to an invoice/estimate and the item has a price set in the pricebook but it is added to the invoice/estimate as a zero dollar item? It's not something that we can replicate. We find invoices/estimates with this maybe once or twice a month and we can't figure out how/why  it's happening. 

[Steveng]

Could it be a duplicate task?  Probably just a glitch, did it effect the total?  Also, I'd run that task code in a report and look for past issues as well.  The ST help desk should be able to identify when that task was created and what was selected and updated before the tech saved the task.  They have done some pretty cool dig-in queries for us in the past.  Good luck on that one.  Sounds like a pain.