On the desktop, you can link an estimate or an invoice to an opportunity card and it shows up on the opportunity card. When viewing that same opportunity card in the mobile app, it will show that there have been transactions, but will not show the estimate or invoice to reference what is attached to that card. Which hinders people who work from the app in the field.

Additionally, when the estimate or invoice shows up attached to the opportunity card when you fix this bug, please make sure that the invoice and opportunity are clickable and openable.