We have often had the same issue with pipes in profile view. The key is to extend the profile view well beyond the last structure - 100' or more. You'll be able to label the structure, or to see the label(s) you've already created.
Even though I had the alignment extended past the end of pipe/structure, I was not able to label it. I extended the alignment WAY past the end and yes, I was able to label the pipe. I also went back and just extended the profile view, it works. And doing some other testing, if I extend the profile view 34.07' more, the label works, if it's .01' less, the label will not show.
I'll get this problem sometimes if the profile view reads from right to left. Change the style to left to right reading, label the pipe, then switch back to right to left reading.
Is a portion of the pipe outside of the alignment station range? If so, Profile View Properties, Staions tab. Put in user values to make the profile view long enough to see the full pipe. You should also see the labels if this is the issue.
SIG - I had the same problem and was trying to right click on the pipe in the profile but it would not add a label. When I selected annotate from the Ribbon and did what you said
"One thing I've done without realizing was trying to label pipes in profile with plan view label. Make sure you select sinlge part profile view when labeling profile."
It worked. The label appeared. The right click add did not work.
Thanks for your post. It helped.
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