When you make a structure like the schematic below with a lever on top of the full block, flick it on, and remove it, the repeaters stay on. Although this is useful and can make a t-flip flop, it is peculiar so I decided to report it here. As placing pictures gave me a “missing token” error, I made this schematic:

B = Block (with lever on top)

R = Redstone

T = Repeater

RTRTR

T       T

RTBTR