Yes it has happened! That is one reason that ESP's (electric submersible pumps) are being used, lower steam pressure but "superheated" (and less driving force) to keep SOR's down (steam:oil ratio). I believe CLL's reservoirs are much deeper than Deer Creek's. Many of Deer Creek's management team and commissioning team have and are working for CLL.

Quote from article:

To date, SAGD has promised steady bitumen wealth but delivered inconsistent production and rising costs because no two projects are finding the same conditions. Alberta’s oilpatch regulator, the Energy Resources Conservation Board, has a little-known website where it annually posts in situ progress reports. They make interesting reading. In 2006, Total E&P Canada Ltd. suffered a major blowout after injecting too much steam at a well pad for its Deer Creek–Joslyn project, creating a 300-metre crater in the forest. It also reported “overall inability to inject steam at higher rates and thus ramp up production rates.”

see article!

http://www.canadianbusiness.com/technology/trends/article.jsp?content=20080915_198703_198703