Bug on 123.0.1, installed on Win 10 via Steam. Tested with pak64 and pak128.
When the game's time is set to the lowest speed possible, it freezes for a few seconds every time when paused. After a few seconds it runs normally. Does not freeze when unpausing, or when pausing when game's time is sped up.
If you decelerate the game using the multipliers, you also decreasing the number of simulation loops per second, which are those that process commands (like pause). This slowdown tool is only for debugging, especially since one can built in pause mode.
If time passes too fast, I rather suggest to increase the bit_per_month setting.