[BUG] nrf9160 (Cortex-M33) with tickless enabled randomly locks up in ostest

### Description / Steps to reproduce the issue

nrf9160 (Cortex-M33) with tickless enabled randomly locks up in ostest (in random places).

Tested with config: `./tools/configure.sh nrf9160-dk/ostest_tickless`

When tickless is disabled, the problem doesn't occur.
CONFIG_DEBUG_ASSERTIONS=y makes the problem not occur (or its harder to trigger).

The problem doesn't occur on release/12.6 (or its harder to trigger).

### On which OS does this issue occur?

[OS: Linux]

### What is the version of your OS?

Arch Linux

### NuttX Version

nuttx-12.7.0-RC0, master

### Issue Architecture

[Arch: arm]

### Issue Area

[Area: Kernel]

### Verification

- [X] I have verified before submitting the report.