Delay compared to other microphone

[nibill]

I have a setup where I have multiple microhpones positioned across an apartment and all record the same audio at the same time. The ReSpeaker are connected to a Raspi4 and to the same Raspi is also a Rode NT-USB mic connected (so each Raspi device has two mics one ReSpeaker and one NT-USB).
Now I have realized that, even though all mics start recording at the same time, there is a certain delay within the ReSpeaker recordings (at different locations), but also between a ReSpeaker and NT-USB recording, which are at the same location so there is no time delay. Does anyone have an idea what might cause the delay on the ReSpeaker?

Thank you.