timelapse – During interval timer shooting, NIKON D5600 overexposes photos randomly

I am having an issue with my camera. At random, it will overexpose photos during interval timer shooting. It’s generally fine at the beginning, but as time goes on, there are more and more overexposed shots. The time on those shots is the same as on the ones that are properly exposed.

Here’s my last timelapse, you can see the overexposed shots:

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I am thinking that either the aperture is not being set properly on the lens, or the shutter is broken. How can I diagnose this so that I can know if I need to get anything fixed? It never happened when I was taking pictures normally.

Overexposure – Nikon D5200 overexposes pictures in "Auto" mode

I recently (2 months ago) bought a Nikon D5200 as my first DSLR. Everything was fine until a few days ago, but now it seems that every shot I take in auto mode (including the various modes like landscape / portrait, etc.) is completely overexposed and washed out. The only way to get a normal shot is to switch to "A" or "S" mode and manually adjust the exposure compensation to something large and negative (e.g. -5.00).

In Auto mode, the ISO value is set to Auto, the WB value is set to Auto, as in most cases. So I'm amazed at what causes the overexposure and why this problem suddenly occurred. Even in aperture priority mode "A", if I manually set the ISO value to 100 and the WB value to "Direct sunlight", the pictures will still be too white / washed out unless I set the exposure compensation.

I tried to reset the factory settings by pressing and holding the two buttons. I also reset the shooting menu and everything else I could find to reset, but in Auto mode the pictures are still overexposed.

Does this mean that my camera has been smashed and needs servicing, or is there anything else I could try?

Here is a picture of the camera lens attachment area:

Fastening area 1

Fastening area 2

Exposure – Canon 70D overexposes or underexposes frequently shots

It really bothered me, I do not know what it is, it's difficult lighting conditions for the camera, it's my settings, but I get very often wrongly exposed images with my 70D. Here are some examples:

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P-mode (1/200 F7.1 ISO 100)

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P-mode (1/500 F11 ISO 100)

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P-mode (1/125 F5.6 ISO 200)

These pictures were taken in P-mode, RAW, evaluation, auto-ISO, min. Shutter speed 1/125. The pictures you look at are JPEG files. I have opened and converted the RAW files in Digital Photo Professional so that some are in camera processing, but there is little difference in exposure to the RAW file.

When it comes to the lens, I use Tamron 24-70mm F2.8 G2 and a lens hood.

Any suggestions?