That’s what we in the trade would refer to as “a wee bit naughty”.
Is the truss secured to the forks of the telehandler?
The truss’ll be relatively light though and as long as the telehandler has sufficient reach to clear it over the protruding scaffold upright and allow it to be unloaded at high level, nobody’ll die. Probably.
Internal standards in construction companies vary wildly. I’ve worked in places where that picture would get the site manager and everyone else involved sacked on the spot.
I’ve also worked for companies where the same photo would be greeted with bemused cries of “What?”
HSE would take a dim view I suspect.
The safest way would be to build the entire roof structure on the ground and crane it on in one go. The really dangerous bit is for the guys who’re clambering about up there trying to assemble the trusses and board the roof.