Repeat transmissions missed

[cimba007]

Setup:

Node A: rc-switch sender https://pastebin.com/dajLZSe3

Node B: rc-switch receiver https://pastebin.com/RG29GGrs

My Problem is that the sending Node A sends the message 22 times (checked with oscilloscope). My Node B only receives ~half of the messages, only 10 received

87656;10;2552

Am I doing something terrible wrong or can some1 point me in the right direction?

Both nodes are Arduino ProMini @ 8MHz Int RC-OSC. Node A uses the defaultish sender from this bundle (https://www.ebay.de/itm/433MHz-RF-Sender-Empfanger-Kit-Funkmodul-Transmitter-fur-Arduino-Raspberry-Pi/112277710415?hash=item1a2445e64f:g:naAAAOSw5cNYg-CN)

Node B usess Receiver from this bundle (https://www.ebay.de/itm/315MHz-433MHz-Wireless-transmitter-receiver-Wireless-module-SYN115-SYN480R/272387133128?hash=item3f6b89cec8:m:m27-PiH0fK7Oi9HdN9Kr-0w)