I have seen this before, a few months ago on a release prior to 4.0. (one of the 3.60 ones).
We are now running 4.10.730 and I have not had a repeat since 4.00.729 at least.
Just to help your confidence...
Ive been using Rational Rose since about 1995 I guess and Rose 2.7.1 with Booch. I continued to use it across a number of projects (my entire career has almost been spent being a rose designer/software engeer) thru 3.0, 4.0, 4i, 2000 and 2002 enterprise suites.
Now with Rose at 2500UKP a shot its not pretty. 2 years ago whilst working for a global shipping company (a very very big one at that) we got rose 2000 enterprise. We were a c++ project and their code generators were privously very good. At Rose 2000 they re-wrote they code generators and re-introduced faults that I had outstanding in 1997....to the point where i could not recommend use of the tool for code generation - but not before I tried tech support.....
Support at Rational was less than humourous. I generally got nothing fixed very slowly. In fact rational support spent their whole time emailing me to say - do you still have the problem? hmm. let me think. You havent shipped a fixed product...what do you think?! Very very unresponsive.
Ive been using EA since August 2003, Ive used it for business process modelling, and general use-case, and OO modelling and requirements tracking. In the last 2 months another project of mine has turned towards using EA for C++ code generation. Sure we have some issues....java is much better catered for than C++ at the moment - however Sparx support is exemplary - extremely responsive and problems DO get sorted. We experience roughly one build a month, which is great - we get to keep on top of things and still control phase in of new versions throughout the team.
A mate of mine also uses EA at the company he works at..he made requests for enhancements to the macros for code generation....and viola they have been incorporated and are available in the latest build. Cant say Ive ever had rational do that for me.
All said and done my faith after over 10years of using rose, has now been firmly placed in EA, and I dont feel cheated, short-changed or in any way like I am using an inferior tool. Im not.
EA delivers much much more than Rose did, especially when considering costs of kittting out a whole team or department. More importantly Rose's quirking sharing of files through .cat files was never pleasant - and ive worked in 60 developer teams using rose....tools | check model if I recall always produced a healthy list of errors - which at times saw me resort to fixing the .cat by hand

EA has a significant advantage in using corporate databases and for us combining it with MySQL is perfect - especially given the cost - and the whole team works on a single living model.....and it works very very much better than .cat/.sub files ever did for me...
The current company I work for is evaluating EA for recommendation as a corporate standard, we have a number of issues, mainly related to c++ code gen, but most of these are either minor issues, or we have workarounds. We are certainly developing at full speed.
Guess the bottom line is, make sure you are on the most current version, and dont worry so much - the price is very very misleading - the product certainly hits with the features of a 2500 UKP product, but hits the project budget in a very minimal manner....you can spend the rest of the money on a dev team bevvy when the project delivers!!!