After gaining a better understanding of the issue, I realized this poses a huge limitation to large organizations who administer data by publishing at the portal level and have users who include the data in their ArcGIS Online applications. If possible, please fix this bug!
"When editing ArcGIS Server feature services in ArcGIS Online, the new symbology set in the web map reverts to the symbology settings from ArcGIS Server."
Why this is a problem- Scenario:
If an administrator publishes an editable feature class for their department in portal and expects to use it in a variety of editing applications in AGOL, any time they click the edit tool the symbology it will revert to that published.
This may pose an issue for organization users or volunteers(general public) who may be editing in AGOL and aren’t aware of this issue. It may be disconcerting or problematic for the end user when the symbology switches like that (especially if it is a drastic switch similar to my example below).
Currently the only workaround for this is to publish multiple separate services with pre-set symbologies to Portal to use in AGOL apps/map that need specific symbols and have editing turned on.