LD_LIBRARY_PATH is concatenated to itself

I am trying to use the library envpool to parallelize Open AI gym environments. I run the simplest example provide by envpool, which looks as follows:

env = envpool.make('HalfCheetah-v3', env_type='gym', num_envs=100)
obs = env.reset()
act - np.zeros((100, 6))
obs, rew, done, info = env.step(act, env_id=np.arange(100))

It works as in it produces the desired output, but it also throws the following:

Could not load dynamic library 'libcudart.so.11.0'; dlerror: libcudart.so.11.0: cannot 
open shared object file: No such file or directory; LD_LIBRARY_PATH:
:/home/user/.mujoco/mujoco210/bin:/usr/lib/nvidia:/home/user/.mujoco/mujoco210/bin:/usr/lib/nvidia

Moreover, when I run echo $LD_LIBRARY_PATH I get the same directory. Why is it duplicated and how to fix it? My .bashrc is as follows:

export PATH
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/home/user/.mujoco.mujoco210/bin
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/lib/nvidia