TV Samsung 50' UE50TU7070 - Wake On Lan strange behaviour

Hi all,
my wired to router TV doesn’t work good with Wake on lan.
Everything works good with Smartthings, Alexa and hassio.
Only wake on lan didn’t works good.

if i shutdown my tv, wake on lan works if i try to turn on TV few seconds later
but, for example after minutes, if i say to Alexa “Turn on TV”, my TV turns on after 1,2,3 or 4 mins later.

i noticed this in device history in hassio console:


it seems that my TV is reacheable every 5.30mins for 40secs.
in smartthings button clickable only in this range.
i see other people has the same problem but probably nobody noticed this.

any suggestion?