Is there any problem here? First time in 3 years to run into this plumbing under a kitchen sink. The PVC goes into the main drain which is galvanized
After the trap, when the pipe tuns down to an additional horz run - all require an increase in the pipe diameter (Vertical Leg Waste Fixture Drain).
Where the two sinks/drains meet at the “T” - there should be a directional fitting, not a tee.