Messages sometimes show up late and/or in bunches

• [x ] I have searched open and closed issues for duplicates
• I am submitting a bug report for existing functionality that does not work as intended
• I have read https://github.com/signalapp/Signal-Android/wiki/Submitting-useful-bug-reports
• [x ] This isn't a feature request or a discussion topic

Bug description

Typing on the desktop client and after awhile I heard my phone buzz. Opened it up and a flood of signal messages come in that were from the last several minutes (15 minutes maybe)

Steps to reproduce

• use desktop client, message friends on signal.
• sometimes hear phone buzz
• pick up phone and turn on screen

Actual result: signal messages from recent history flood in
Expected result: messages come into phone roughly at the same flow as desktop while on the same network

Device info

Device: Samsung galaxy s9
Android version: 9.0 stock Verizon
Signal version: 4.35.3

Link to debug log

https://debuglogs.org/6d156ab53db2297c534498e59937440ab48bb8d5ef77527afd850adcaa89c26f

Start with the supplied reproduction steps on the listed Samsung Galaxy S9, Android 9, and Signal 4.35.3 environment, then inspect the linked debug log for the delayed delivery and batching period. Done means identifying and fixing the cause so messages arrive on the phone at roughly the same flow as on the desktop client, with the behavior verified against the report.