Blind Transfers after v20

[gfit]

I have a mixture of phones that are all on firmware versions that are supported by 3CX at multiple customer sites. All phones affected are current firmwares or have been replaced (post v20 install). We use Grandstream GXP2170 and a spread of Snom phones. Customers keep telling us that "calls drop when we transfer." After seeing it in the field, the hard phones are now attended transferring, even with the blind setting turned on. On the Grandstream devices, there is a "dynamic transfer" and if you set it to "Static" it will just make you press the soft button twice to blind transfer. In version 18 transfers worked as follows: Answer call> Press Transfer> Input destination. I am not about to make custom profiles....for something that used to work and increases support cost. I see lots of dead posts on transfers. What can we do???