Checksheets process slowly in APM Foundation when either Process Immediately = True or set to use Remote Transaction Broker to process checksheets. To avoid the loss of a Remote for potentially a significant amount of time, the user wished to use the Remote Transaction Broker to process the checksheets but, APM Remote when set-up to use the Remote Transaction Broker shows no indication post synchronization that a checksheet is already awaiting processing..
This is a 2 layered problem. The immediate workaround to improve performance of the APM Remote Synchronization is to set-up the APM Remote and APM Remote Service to "Process Transactions Immediately" but to also enable "Differential Downloads". Differential downloads will reduce wait time because APM will not need to rebuild the all checksheets for the APM Remote tablet each synchronization, it will only consider those checksheets that have had a change since the last synchronization.
A bug was reported, VSTS#66199 - "Processing of APM Remote Checksheets and Indicator reading using Full Synchronization is very slow" to review the performance of the full download synchronization.
An enhancement request was launched, VSTS#128253 - Enhancement Request - Checksheets awaiting processing by transaction broker need to show pending processing in APM Remote after sync" to review ways of indicating with APM Remote which Checksheets are awaiting processing via the Remote Transaction Broker.