short video how to fix this issue. Ofcourse it is 100% non professional, home issue solving...

First off: I'm having this issue with the failsafe-enabled version of the FS-A8S too, thanks for showing us how you fixed yours! Will try asap.
Second of all: How on earth did you come to this solution?

wow.. oddest fix i've ever seen. So you think you are getting EMF interference or something from motors spinning??

I was conversing with OP through the comment section on his YouTube video about this. In retrospect it's actually odd that they didn't add an EM shield to the sensitive parts of the pcb like all the bigger RX's have because it's become apparent to me how effective and necessary those shields are. A shield would obviously add to its weight and dimensions though, which are exactly the properties that ppl will most likely care about when considering this this tiny RX for in the first place. As far as I'm concerned this product is kind of broken, as are all the other unshielded receivers.

It's very relevant *where* the RX is placed. If you place it far from the PDB then quite quickly you'll have zero packet losses. Distances are small though, like >5cm away is enough to see drastic improvements. That distance seems trivial but on these tiny compact builds  5cm is often a luxury we don't actually have. 

As for the true source of the noise I'm not completely sure if it's the motor noise or EM fields from the amount of amps going through wires from the lipo to the PDB. The loss of transmission is intensified when you give more throttle, or to be exact how much power is going through the system. I though I was fine at one point when simply doing throttle punches with the props off. When I did a very simple throttle increase with the props on I had a failsafe again.

Applying the shield using OP's method becomes necessary. The mod didn't work as well for me as for OP but I must not have covered the RX up as well as he did and I didn't re-iterate yet.

Actually it is also how flysky has "fixed" the issue on v2 of this rx. It is wrapped in small shielded "case". I will check if there are any other differences on pcb between versions.

Interesting

Yeah that would be nice if you could compare. I'm not sure I follow with what they fixed. As far as I know the newer version had a failsafe mechanism where the first one didn't. As for its design, I'd expect both versions to be equally sensitive to close RF interference if the receiver chips aren't shielded (which they aren't in both versions).