Normally when viewing playback from Xiaomi cameras I can see in a different shade when movement was there - but with my Xioami EC3 all recording is shown in one colour. Please help.
Not sure what you mean here, how the movement is recorded is based on the camera quality and if it has a specific function. Need to check the manual to your camera, I would also look for some reviews.
There is an option called playback - that's where you view the recordings. On there you have a timeline, but the timeline is shown in different colours - e.g. light colour when records and darker colour when movement is detected. At least it has different colours on other cameras, which I have seen e.g. on youtube and in my own other cameras.