Light blue versus dark blue on bottom of model

[iguanaman 0]

I noticed that when I place a model on the bed sometimes the bottom appears dark blue and other times light blue.  I can lift it up and drop it again and it will sometimes switch to the other blue.  Which is correct?  Should the bottom be dark blue, light blue or are they the same?

 

Edited March 20 by iguanaman
Uploaded images showing example

[Slashee_the_Cow 450]

It would help if you could provide some screenshots, but as a general rule, if you're looking from underneath the model, light blue = touching build plate, red = needs support, green = below build plate. Areas not on the bed but don't need support will be coloured with the material colour.

 

What colour material do you have it set to? Because if you have it set to a dark blue material, that could be causing some confusion.

[iguanaman 0]

Added images to show example.

No material color assigned.  Typically the model is yellow in Cura. 

Edited March 22 by iguanaman

[iguanaman 0]

From another user (Asterchades) on Reddit:

 

"Light blue is exactly resting on the bed. Dark blue is beneath the bed. That it changes in this case is likely to be rounding errors on the floating point numbers used internally to determine which colour it should be."

 

This was the answer I was looking for.