Nearly a year and half back, I posted a blog about Fast Dormancy here. This issue has surely been fixed in most of the devices and the networks are able to handle the issue even if the handsets have not been fixed. I found an interesting table in a Huawei journal that shows the timings used by different devices that are being reproduced for people who may be interested.
Change In the Past 5 Years - PC vs. Mobile
18 hours ago