When Signs Plug Flowing Water Excess Water Becomes Suspended

When a Flowing water source is plugged by signs excess water becomes suspended in mid-air as if the signs weren't there

to recreate this make a square with nothing in the middle
B=Block A=Air
BBB
BAB
BBB

On One Side Add A Extra block adjacent to the gap that you put a sign on
LIKE THIS:

1.
S=Block With Sign
ABA
SBA
ABA
2.
ABA
AAA
ABA
3.
ABA
ABA
ABA

4.
Place Water in the gap (layer 2)

5. Where the water first flows out place a block so that if you placed asign on it it SHOULD block the water and contain it

6. Attempt to block the water with the sign i talked about on step 5

BYE

(P.S Sry If this is a duplicate I did research)
(P.P.S Reply if you need specific images or whatnot im happy to provide)