Apple support contacted me Wed night and sent me a list of 10 questions. Interestingly enough, I found from answering them that I was able to send a calendar entry, including a location, from iCloud.com and the invitee received it! AND I was able to send a calendar entry, including a location, from my iCal app on iPad, iPhone and MacBook Pro to an invitee at an iCloud address and they received it!
So it appears from my troubleshooting with Apple that sending calendar events with locations to invitees will work if sending to an iCloud invitee or if sending from directly from iCloud.com. I am sending my data to Apple now and will have another conference Friday morning.
If you would like to go through the process yourself and give your findings to Apple, maybe we can get to the bottom of this issue. 🙂
1.- How is this customer sending their invites (Steps you do to send the invite, and the devices attempted)?
2.- Who are they sending their invites to (A few examples)? Other iCloud accounts?
3.- Can those same recipients in turn send the customer an invitation? If so, what happens?
4.- What happens if the customer sends directly from icloud.com? Is there an error or does it act as if it was sent but is never received?
5.- Does the same issue happen for the customer if their device is connected to a different network?
6.- What lead up to this issue beginning? Was there a change to the account's setting or files prior to this issue? If so, what were they and when did this happen?
7.- Does the issue happen when sending as @me, @mac, and @icloud or just some of these?
8.- Does the issue change if the customer sends an event with no attachments, notes, links, or location data?
9.- Does the issue persist if the customer creates a new iCloud Calendar and sends a new invitation from the new Calendar?
10.- Include a copy of the ICS file that is not sending
macOS
The easiest way to do this is to CMD Click on the event itself from the macOS calendar app and choose "Mail Event".
Have the customer email the ICS file and info it generates