From what I gathered (simply by reading here and at the various FN forums) I think they had some production problems and could not keep up with demand, this resulted in some people getting frustrated and the potential for negative customer service. They were selling batches out faster than they could build them and the backorder would last for several weeks/months.
Rather than deal with the potential for establishing a bad reputation, they suspended sales and production until they could get their production line sorted out.
I hope they do get the assembly issues sorted because it's a fantastic product and makes the rifle perform MUCH better. I have no affiliation with them other than as a satisfied customer. The best way I found to get in touch was via email
[email protected].