As far as I know, those engines are like their predecessors, non-adjustable lifters (buckets).
Did you double check the level of engine oil on the dipstick? Did they underfill or overfill the crankcase? Also possible that they left something (tool) on the engine, left off the oil cap, etc. - something really obvious.
Less obvious is if there is any damage to the valvecover baffle. This was an issue with the 8th and 9th gen Corollas - a technician that was not careful using the oil service gun at many quick-lube places, could end up bending the baffle down to the point where it was actually touching the camshaft.
If the noise goes away - I wouldn't worry about it too much. Engines will tick for a minute or so, until they build up enough oil pressure. A lower viscosity oil, like many synthetics, could exacerbate this ticking noise.
Since the noise is more pronounce when loaded - could be any number of things, some not very good. I'd be tempted to take it back and complain about it - at the every least, start the paperwork to indicate there was an issue immediately after the service.