Incoming IVR playing on/over current call

Hi, hoping someone can share some insight here.

I installed a new PBX in the office using the latest distro of FreePBX (Stable-4.211.64-5).

We have twice experienced a situation of whilst on a call with someone the IVR just starts playing during the existing call. Herewith the details of the situation.

We have 3 POTS lines coming into the system which all go to the same IVR. If no keys are pressed the IVR will time out and send the call to ring group 601.

Now, we received an incoming call which went to ring group 1 - the user who answered blind transferred the call to say extension 1007. A minute or two later the user on 1007 (and the external person they are speaking to) hear the IVR start playing. After the IVR has stopped playing it times out and sends the call the ring group 601 (all of this audible to 1007 and the external caller). Someone answers ring group 601 and then they are also part of the conversation (so now extension 1007, external caller and the person who answered the ring group again are all speaking to each other).

We are using 3 x Linksys SPA-3012s for our POTS lines. It almost seems like one of the SPA-3102s is “faking” an incoming call whilst already busy with a call and thus this “fake” call (with no user on the other end) is being linked with the call that is already taking place.

Both times this happened it seemed to only happen with the same SPA-3102 and whilst the user was busy with an incoming call from that same SPA-3102. Both times the call also went to a ring group first which was then answered and then transferred to a different extension.

Not sure if this makes a difference but I did recently change the 3 inbound routes (which each had one of the specific DIDs in and then sent calls to the IVR) to a single inbound route which did not specify any DIDs and thus sent “any” call to the IVR. I did change it back to the 3 separate inbound routes again to see if maybe that is not the issue (time will tell).

Just wondering if anyone has experienced this yet? Maybe I could upload a “call log” type of extraction maybe that someone could help with?

Much appreciated!!!

Have you verified that your POTS lines are wired correctly and not crossed?

Yip, definitely not the POTS lines themselves.
Hasn’t happened again since I made 3 separate inbound routes instead of just the one. Then again, it hasn’t even been a full 24 hours since I made the change so keeping my fingers crossed…

Replaced the 3 x SPA3102s I was using with a Grandstream GXW-4104 and the problem seems to have gone away…