First, look at the LTSpice depiction (below) of you feeding an input capacitance through a resistor and measuring the voltage across that C.
You should see about 9 or so mV across the C.
Now make a wire from the top of the parallel connection of L1/C2 to the wire above it.
How many volts now? Oops! Where did the "impedance" go?
Does that make sense to you? Why does it (or not)? Can you explain it?
This is one of the confusing thing you are running into with your measurements.
Version 4 SHEET 1 880 680 WIRE -320 64 -432 64 WIRE 128 64 -240 64 WIRE -432 96 -432 64 WIRE 0 96 -112 96 WIRE -112 128 -112 96 WIRE 0 128 0 96 WIRE 128 144 128 128 WIRE -432 192 -432 176 WIRE -112 224 -112 208 WIRE 0 224 0 192 FLAG -432 192 0 FLAG -112 224 0 FLAG 0 224 0 FLAG 128 144 0 SYMBOL cap 112 64 R0 SYMATTR InstName C1 SYMATTR Value 1.4p SYMBOL cap -16 128 R0 SYMATTR InstName C2 SYMATTR Value 251.9p SYMBOL ind -128 112 R0 SYMATTR InstName L1 SYMATTR Value 100u SYMBOL res -336 48 M90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R1 SYMATTR Value 10Meg SYMBOL voltage -432 80 R0 WINDOW 123 24 124 Left 2 WINDOW 39 0 0 Left 2 SYMATTR InstName V1 SYMATTR Value "" SYMATTR Value2 AC 8 TEXT -466 248 Left 2 !.ac dec 1e6 999999 1000001