Problem

RecurrentThread.__LoopFunc_0 — the loop body used when interval is None or interval <= 0.0 — reads the wrong attributes:

def __LoopFunc_0(self):
    while not self.__quit:
        try:
            self.__loopTarget(*self.__args, **self.__kwargs)
        except:
            ...

The constructor stores the loop parameters as self.__loopArgs / self.__loopKwargs:

self.__loopArgs = args
self.__loopKwargs = {} if kwargs is None else kwargs

Because of Python name mangling, self.__args / self.__kwargs inside __LoopFunc_0 resolve to _RecurrentThread__args / _RecurrentThread__kwargs, which are never assigned on RecurrentThread (only the base Thread sets _Thread__args). So every iteration raises AttributeError, which is swallowed by the bare except. The result: the target never runs, and the thread spins in a hot loop printing the same error. The timer-based __LoopFunc (the interval > 0 path) correctly uses self.__loopArgs / self.__loopKwargs.

Reproduce

import time
from unitree_sdk2py.utils.thread import RecurrentThread

calls = []
rt = RecurrentThread(0, target=lambda: calls.append(1))   # interval <= 0 -> __LoopFunc_0
rt.Start()
time.sleep(0.3)
rt.Wait(timeout=1.0)
print(len(calls))
# 0, and stdout is filled with:
#   [RecurrentThread] target func raise exception: name=AttributeError,
#   args=("'RecurrentThread' object has no attribute '_RecurrentThread__args'",)

Fix

Use self.__loopArgs / self.__loopKwargs in __LoopFunc_0, matching __LoopFunc. After the fix the target runs each iteration and args / kwargs are forwarded correctly.