Can AC and DC components both exists across the same point within the filter RC series network in parallel with the diode in the power supply?
It is a two-switch forward converter. Here's the simplified schematic:







simulate this circuit &ndash; Schematic created using CircuitLab

SW1 and SW2 are primary switches and they both open and close at the same time. 

When SW1 and SW2 close, dot-end of the primary gets more positive than its no-dot-end, so does of the secondary according to winding ratio, then DS1 conducts and DS2 cuts-off. Current is fed to load through LO and CO.

When switches open, de-magnetization current follows DP2->primary winding->DP1->Vbus path to reset the primary. No-dot-ends of the windings gets more positive than their dot-ends, so DS1 cuts-off. The energy stored in LO is transferred to the load by the help of DS2.

R201-R202-C202 and R203-R204-C203 are snubbers to protect secondary diodes.

As described above, there's a controlled switching action. There are square-wave-like signals across the primary and secondary of the transformer. So its quite normal to see both AC (because they vary by the time) and DC (because they have a "mean" value) at all the junctions before LO inductor (Its named as L201 in your schematic). If enough filtering is not provided, you can even see "via an oscilloscope" both AC and DC at the output nodes. 

Note that the switching frequency should be around a few tens of kHz, so some digital multimeters cannot measure the signals having that level of "high" frequencies correctly.

Sorry for crappy English. 
hth.