The tran+stb simulation phase curve declines from -150 degree

Hi all, I've encountered an unusual issue. When performing tran-STB co-simulation on an OPA with switched-capacitor feedback, I observed its phase curve starting to decline from -150°. As this is my first time dealing with switched-capacitor feedback loops, I'm uncertain whether such simulation results can be considered valid for stability assessment, or if there are compensation design flaws in the circuit? Sincerely appreciate your insights.
The simulation results：

The schematic：

The specific circuit configuration is as follows:
The switching sequence operates such that transmission gates TG11 and TG12 switch simultaneously, while TG21 and TG22 also switch in unison. When TG11/TG12 are on, TG21/TG22 are off, connecting the capacitor between VA and VCOM (0.5VDD). Conversely, when TG21/TG22 are on, TG11/TG12 are off, connecting the capacitor between INP and an output node.

Given that the OPA incorporates six identical feedback loops in both upper and lower paths, transient simulations reveal two distinct circuit states:

（1）A capacitor bridges the OPA's input and output

（2）While maintaining the input-output bridging capacitor, two additional capacitors are connected in parallel from the OPA's output node to VCOM.

I selected two time points corresponding to these states, which yielded the aforementioned simulation results！

Additionally, I attempted Pole-Zero (PZ) analysis but encountered uncertainty regarding output terminal configuration for the fully-differential output OPA