I came across this problem today as well.
I investigated options by confirming that the text was treated the same way on all my pages.
(1 out of 5 pages appeared darker)
I went into various settings to find results but to no avail.
I created a new page and pasted without formatting. The text looked the same as the other pages until I copied all the images on the page at once, then the text appeared darker. I undid that action and pasted each image separately to find the problem. I found the image that was causing the error. In Photoshop, I opened the image causing the problem and 1 of the pictures that placed fine to see what format and color mode it was saved as and found that the image causing the problem was a png format. That alone would have been fine; however, it had a transparent border around it. I am guessing importing png into InDesign keeps the transparent attribute as opposed to other formats converting it to white. To solve this problem I cropped out the transparent border and saved the image as a jpg and placed it on the file in InDesign and voila...the text did not change.
I hope that helped you and saves you the amount of time of investigating!
Good luck.