Could well be - although most posts I can find on the Kodi forum seem to be pretty old if they have similar problems. It appears that AAC (SBR+PS) = HE-AAC, for what it's worth...
Thoughts to nail this down further:
1. Does VLC play that audio stream? ==> tvheadend is working and it's a Kodi/Pi/Openelec issue
2. Can you record that channel? Does Kodi play it back then? ==> it's a tvh addon issue
3. Can you play the recording on anything else? ==> tvh is recording it okay, so it's back to Kodi in some guise
... and so on. If you can record something and upload it then I can try it on OpenElec (non-Pi) and Kodi on some other platforms to see how it plays there. That may help nail it down.
It doesn't sound like a tvheadend issue, though, but let's see if we can isolate it. The fact they play in the WebUI under Windows suggests that the stream is okay and that it's a Kodi issue - perhaps specific to the Pi for some reason? We have some Debian Pi users on here as well, so that's another place to test - in fact, I think I have Kodi on a Pi2 somewhere as well...