One of three panels failing?

Today because I've had charging issues I ran a spot check of my 12 volt system (exterior lighting and water features only) and found the following individual currents and voltages in mid day (optimum tilt aspect, not winter) :
Note all three were tested alone, and NOT in parallel.
200w NewPowa 5.4 amps and 16.5 Vdc
150w NewPowa 1.4 amps and 13.0 Vdc
125w BP solar (~10 years old) 6.2A and 14 Vdc.
150w NewPowa 1.4 amps and 13.0 Vdc
125w BP solar (~10 years old) 6.2A and 14 Vdc.
The Newpowa 150 was bought in May and the seller wrote me suggesting that my connection method was at fault? Is she off base? or is it prohibited (I never read this) to connect panels from different makers and wattages.
"May I know if you are paralleling these panels with different wattage? If so, it is not recommended.
Because the low wattage panel will pull down the output of the high wattage panel."
Because the low wattage panel will pull down the output of the high wattage panel."
Any help would be appreciated.
Comments
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.