It has been observed that when using PHY CODED, T_IFS is not stable.
It has been observed that it differs sometimes even 16 us from specified 150. This leads to connection timeouts with some controllers.
After couple of discussion it turns out that it is related to SHORTS we use for TX/RX. It turns out on NRF52 it is better to have own timers in the controller and not relay on SHORTS from the radio especially when using PHY CODED.
In this Jira we should understand how big changes it requires and possibly try to do it.