I had a few bubbles form in my substrate, but it usually happened around the compacted sand at the glass substrate interface and wasn't really a problem that a quick poke with a stick didn't sort, that was until my planted aquatic inexperience caught up with me and led me into purchasing and planting a few very 'nice looking' Opheopogons in my tank. I could tell something was not right after a few weeks, the Opheopogons looked amazing, nice and green and palm like, but something just wasn't right, I could swear the fish were looking at me with 'Help' faces, so I did a quick investigation on my recent planting because it was nameless from the shop and 'recommended' as a lovely plant. Ahh it's an Opheopgon and according to lore a plant that gets commonly unscrupulously sold by aquarium shops as an Aquatic Plant when its actually more of a Terrarium plant. I can reveal now that the worst smell I have ever experienced was removing that effing plant from my tank, this outdid standing on a North Sea Beach with a whole winters worth of storm dredged Kelp rotting 20ft deep into the surf with Seal excrement added for extra aroma. The aroma coming from those blackened dead Opheogon roots was similar but with the added Turpene aroma of the most badly creosoted fence in the whole of history. Lesson learned, don't put non-aquatic plants in an aquatic realm.
I can safely recommend that you can poke a stick at it first and act later!
🙂