According to the forum thread, other Lumia 950 handsets have received the build but an undetermined percentage of Insiders still seem to be cut off.
Microsoft has commented on the issue stating that hard resetting affected handsets might fix it. They however suggest not to do a hard reset as they are currently working on an alternative solution.
Microsoft expected to provide a fix
They don´t promise a quick fix but ensure that the issue is given certain attention. Jason[MS], Microsoftie and Forum Moderator has answered to user complaints.
“Definitely have the right Engineering folks engaged internally and this is getting lots of attention. I can't commit to a specific timeline for a fix unfortunately, namely because we don't fully know what the issue is at this time. I may need a volunteer or two to install the Field Medic app and run some advanced update logging.”
Windows 10 Mobile build 10586.29 was released on Friday to the Fast Ring, followed by the Slow Ring on the next day. According to Gabe Aul, Corporate Vice President, Engineering Systems Team it is the first Cumulative Update for the Windows 10 Mobile.
While Windows Insiders are reporting problems to get the update, some Windows 10 Mobile handsets that are not enrolled in the Insider program seem to get build 10586.29. Several Lumia 550, 950 and 950XL owners report that they have received the update including even the AT&T version of the 950.
Build 10586.29 update contains improved application backwards compatibility for Windows 8.1 and Silverlight applications. Lumia 950 and 950XL were both released in November while Microsoft Lumia 550 (codename Saimaa) was released in early December.
Source: Microsoft Answers