Help Identifying Sun Cruiser Tandem Bike
There's been a bike company named Sun making tandems since before WW2.

Brand: Sun
Model: Cruiser tandem
Year: Unknown - probably 1990-2010 range.

The bike looks nice and comfortable to ride, with wide plush tyres, and relatively high handlebars/low saddles it will give an upright ride.
That bike is not built for speed, but for getting out and around in pairs.
The V brakes front and rear, with no third brake suggest its not really for touring, and the timing chain on the right-side with one-piece bottom brackets shows its an entry level bike.
In the Trendy category, it could legitimately be called a 1by because its a single chainring and probably 7 speed derailleur at the rear.

All in all its a loverly bike and would be a pleasure to ride.  Especially in these days of pandemic.
It would also make an excellent platform for a cargo bike conversion, should that be more use to you.
As per Carel's comment, the two cranks are at different positions in their cycle.  A conventional tandem has both cranks in identical parts of their rotation, so that both riders are pressing the same side crank down at the same time.
This makes for a better &quot;feeling&quot; else one rider's cranks push themselves forward at the wrong part of the stroke, and also when cornering.  Though this bike probably doesn't corner aggressively, it is still possible to get pedal strike. To fix this, just unship one end of the sync chain, rotate a crank to match the other, and refit the chain.  There is a chain tensioner under the keel tube which will allow the slack needed for this simple tweak.