Ringing Incoming call gets connected to parked call if user picks up parked call when incoming call rings

I am experiencing he same issue as [Jonas Nimmo]. Any guidance would be much appreciated from the following behavior

prior post(Forum ID 62871):

We are running:
FreePBX V14.0.16.11
Asterisk V13.38.3
Sangoma S505 handsets
Converted trunks and extensions from CHAN_SIP to CHAN_PJSIP in August. This has happened three times since I converted, not prior.
I do not have logs, this was brought to my attention today. I asked the user that handled the calls for call time and incoming CID, but she could not remember. I asked for that info if it occurs again so I can post the log if needed.

operating scenario:
Call 1 received and put on Park (BLF x701-704).
Call 2 comes in and while Call 2 is ringing any user presses Park button to retrieve Call 1 and the following occurs:
Call 2 is answered, Call 1 is brought off Park. Call 1 and Call 2 are connected and user is disconnected from call.

Result is: Unattended conference between our clients, hosted for free on our PBX.

I found and read the previous post and am not satisfied with the explanation of what is happening nor lack of instructed resolution.
IMHO: This is a bug with the FreePBX and/or Asterisk.
The FreePBX system should not be connecting a new incoming call to a parked call and disconnecting the user no matter what the user presses other than a hang up.

So right now my users have to answer each incoming call before picking up a Parked call or hope that they pick up the parked call before the phone starts ringing again…?
Seems kind of crazy to me and something we should not have to be worrying about or implementing a work around for.
The user picking up the BLF parked call should do just that, it is a button press.
The incoming call should continue to ring until the Line button is pressed to pick it up. Again a button press.

From prior post- YES I am sure about that.
From prior post my questions are-
First: Is the call ringing at the BLF destination?
It is parked on hold. I thought this was a waiting area, the parked call is not ringing a destination like a transfer. Or is it?

Why in the heck are the two calls connected?

Why is the user disconnected from the newly combined calls?
This is now an unattended conference call.

Please let me know your thoughts and a better description of the work around or fix implementation if you would.

Thank you very much for your assistance,
Chris

You need to show verbose call logs of this happening. We need to see what is being sent to the system and how it is processing.

You/re using a Sangoma S series, the referenced thread was using another manuf. In order to configure an S series phone such that pressing a BLF button when it’s in the ringing state does not transfer the ringing channel to the BLF destination you need to change the value of P23406 as described in this page:

https://wiki.freepbx.org/display/PHON/Sangoma+P+Codes

I don’t think this option is exposed in the EPM template, but you can alter it by doing a Basefile edit in EPM as described here:
https://wiki.freepbx.org/display/FPG/EPM-Admin+User+Guide#EPM-AdminUserGuide-BasefileEditing