With all due respect, this is not an iTunes issue, this is a playback issue, as the problem is the same across all audio platforms - podcasts, iTunes, Pandora, etc. I'm on iOS 11.4 with a 7 plus, and I've noticed these same issues since 11.3. Sorry folks, but 11.4 didn't fix it. The problem seems to be with the lock screen. If I start a playback with Bluetooth (AirPods mostly) and lock the screen, it invariably drops the Bluetooth. I go into my settings screen, and it has the AirPods listed as still connected, and the playback is still going, but no sound. So I have to disconnect the AirPods, reconnect them, and start the playback over again, this time being mindful not to lock my screen. Super convenient, right? (The issue is slightly different when I have headphones connected physically with the lightning adapter - in that case, if I lock the screen, the music or podcast starts skipping and eventually stops working, or continues to skip even after I unlock the phone).
Most of us on here own Apple products because they work the way they are supposed to work, and do it with as little interruption to our lives as possible. They make our lives easier, not harder. If I wanted a phone that was powerful but has glitches and requires workarounds, I'd just get a Samsung. When will this be fixed?