Not according to most constitutional scholars. However, I believe the practice has gotten out of hand the past 25 years, especially on domestic issues. It has become common practice. No one seems to care.
No President wants to work with Congress anymore. I don't want to hear the excuses of "they won't work with us." That's bull. Reagan got his legislation through by negotiating. Clinton did the same thing. GW Bush issued a lot, but most were dealing with intelligence and defense issues. I still don't like that either.
Obama has issued less than his predecessors, but overall it's a cop out. It means two of the branches of the Federal Government are not doing their job.