It is rather common for home owners to have areas in their home where the drywall tape ripples or comes loose. These areas are often re-taped or patched when re-painting the room.
One of the most common reasons is that the drywall tape was not mudded or applied properly. At times the drywall tapers do not get the drywall mud that they are using to be the proper consistency, or mixed properly. They may have been chatting or not paying attention and did not apply the drywall mud that goes under and over the tape properly.
When this happens the tape may have ripples, bubbles and air pockets or come loose. Dry wallers who are new to the trade often struggle with these problems when they first start dry-walling and taping.
2. High humidity or rain
When the humidity is very high or it is raining, then there may be an occasionally problem with ripples or loose tape developing.
3. Settling and foundation or soil movement
Newer homes which are only one or two years old will often have a some settlement, where the foundation settles or sinks down a little. This shifting or movement may cause the drywall to crack in places and occasionally the tape to ripple in a few instances. ( Read about homes settling )
Homes that are built on soils that are expansive in nature, i.e. soils with clay content or on soils that have low load bearing capacities tend to have foundations that will move or shift. Over half of the homes built in the United States have these type of soils.
Expansive soils, seasonal changes, settling, or heaving of the soil will occasionally cause the homes framing, i.e. the studs, to move; thus some drywall tape may ripple or come loose.
The majority of the time these types of issues can be repaired by either a drywaller, home owner or painter. Many times painters need to touch up or redo the tape in a home before they paint.
Who to consult? Painters and drywall contractors.
Home owners will often re-tape an area where the drywall tape has rippled. Painters and drywall contractors are the most proficient at this type of work.