Similar experience with my 2006 Aurion ATX with 165,000KM. Apparently, the 2GR-FE engines are prone to engine sludge especially if poor quality engine oils have been used or not serviced properly. After a few Google searches, I found a post that explained that engine sludge was blocking oil channels and preventing the oil from draining properly from the valve covers, The PCV valve is then sucking the oil into the intake and this explains why there is exhaust smoke when you first start the engine. Later on a trip to Wagga Wagga, I noticed a significant blue smoke screen when accelerating hard on the highway. Engine oil level was full in the morning and mid afternoon after travelling 600km the oil level was below the low level.
One quick solution is to either replace or remove the 2 valve covers and soak them in degreaser to remove the accumulated oil sludge in the oil channels. The PCV valve also needs to be cleaned so it can operate freely.
Before dismantling the engine, I have desludged the engine a few times. During the return trip from Wagga Wagga to Brisbane, I added about 500ml of diesel before leaving and again after 600km. The new engine oil was totally black and the new oil filter cartridge was clogged with small black soot like particles. I replaced the engine oil and filter cartridge plus 500ml of diesel and checked after 500km. Again the oil filter cartridge was blocked with particles and the engine oil replaced. After further Google searches, I found a posting suggesting using 500ml of auto transmission fluid for oil sludge removal as an alternative to diesel because it contains cleaning additives. I did this and after recently returning from another trip to Wagga Wagga [2600 KM], I have just replaced the oil filter cartridge and topped up the engine loi level with more ATF. Inside the valve cover and side of the valve train is totally clean with no evidence of oil sludge. The excessive exhaust smoke is now totally gone. More Google searches suggested using a synthetic oil to reduce and minimise oil sludge.
Also according to an ex Toyota Dealership worker, the 2GR-FE engines, if properly maintained, should last about 400,000 km before requiring any rebuild work.
So maybe the dealer should consider adding a commercial engine flush product and have you drive around for 125km before returning the vehicle for another oil and filter change. This should reveal whether it is an oil sludge issue or the valve seals do need to be replaced.