ASSERTION FAIL: prepare_cb: Actual EVENT_OVERHEAD_START_US

[marcowidmer]

Describe the bug
Our application is configured with the following option:

CONFIG_BT_PERIPHERAL_PREF_LATENCY=3

When establishing a BLE connection with the Google Pixel , the phone sends multiple consecutive connection parameter updates.

In some cases, we reach the following assertion:

ASSERTION FAIL [0] @ WEST_TOPDIR/zephyr/subsys/bluetooth/controller/ll_sw/nordic/lll/lll_peripheral.c:342
        prepare_cb: Actual EVENT_OVERHEAD_START_US = 19500

To Reproduce
See above

Expected behavior
No assertion

Impact
HARD FAULT

Logs and console output
See above

Environment (please complete the following information):
Zephyr 4.1

Additional context
The issue is caused by an integer overflow, which is fixed in #87066