Colours printing wrong from an PDF indesign file

We are really confused about this, 

The colour of the yellow speech bubble is a yellow CMYK swatch and on the PDF previews as yellow, however, when we got this file printed, two objects came out as green when they should be yellow, see screenshots of the swatches and printed copies.

There are other items on this file which are using this same colour yellow swatch, and are over a blue colour, but they haven't come out green. 

There is no transparency effects or blending modes over any of the items either?

This is really concerning as this issue can potentially affect anything, and has affected stuff previously we have sent to print!