SUMMARY
When accepting an invite to an event from KMail, the event is added to the calendar (visible in KOrganizer), but it's notifications are missing.

If the invite is accepted through Google web interface (Calendar web interface), the event is added to the calendar (visible in KOrganizer), and the notifications are present.

PREREQUISITES:
* 2 Google accounts (A and B)
* Account B registered in KMail and KOrganizer, to see it's emails and calendar

STEPS TO REPRODUCE
1. Create an event in Google Calendar (web view) with account A and send an invite to account B
2. From KMail in account B accept the invite to the event (which will ask you to choose a calendar)
3. Choose the main account calendar

OBSERVED RESULT
The event is added to the calendar, but the notifications for the event are not set (empty). The notifications are visible on the Google calendar web interface.

Adding notifications through the web interface does not add them locally.
Adding them locally, duplicates the event.

EXPECTED RESULT
Event to be created in the calendar (visible in KOrganizer) with the set notifications. Just like if the event is accepted from Google Calendar web interface.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Fedora 29 KDE
(available in About System)
KDE Plasma Version: 5.14.4
KDE Frameworks Version: 5.52.0
Qt Version: 5.11.1

ADDITIONAL INFORMATION

KMail and KOrganizer version: 5.9.3
Not available as a choice in BugZilla.