I have quit touching Citrix since 2015, boy am I grateful it is no longer the product I support/run/design.
Lists of bugs and problems are endless, you are always the first point of blame, yes BLAME, from everyone including networking team, server teams, middleware team, etc and more and more applications are moving to HTML and only crappy legacy apps like that needs ACTIVE-X! runs on the Citrix servers.
You dont need to worry, problem with app? yes call Citrix Team cause Citrix suck but in fact, the app is just plain suck but no one can get off it or admit it. I've seen shit Java applet, Activex, VB6 app, that had to be deployed via XD?XA, guess what if it doesnt run well on the client, it doesnt either on the server, but no one gives a shit and deploy it on XA/XD.
The biggest problem that I had to get out is, less and less enterprise are remaining on the Xenapp/Xendesktop. Leading to less jobs, less pay, and uncertain future. And my friend who worked for Citrix over 15 yrs got fired last year too. Move on people future is mobile and HTML. (and running nginix/apache, lol)