FL allowed?

[klasmalmstrom]

But if there were a prexisting FL the bypasser is attacked by the residual, since residual effects bypassers. That's what I said earlier... but now I wonder, is that right? Unlike ordinary residual, FL residual is traced back to the source, right? So, I think LOS is strung to the applicable bypass vertices, is blocked, and so there is no attack from the FL residual.

Also answered, by another (unofficial) Q&A:

A9.22 & A9.221
Is a unit bypassing an obstacle in a hex where there is a fire lane residual FP – because the center dot of the hex is in the LOS of
the manning infantry, per A9.22 – attacked by this Fire Lane Residual FP if moving out of the LOS of the manning Infantry? If
yes, Which is the DRM is bypassing through OG?
A. Yes. Obstacle TEM.

Are they attacked (the bypassing inf) if the bypass hexside is in the LOS of the manning infantry, but the center dot of the hex is
out of the manning infantry LOS?
A. No.

 

[Pyth]

Actually, there is an (unofficial) Q/A saying otherwise:

A6.11 & A9.22
A unit is bypassing an obstacle. A shot is taken at that unit and a fire lane is declared. The hex being bypassed is in LOS.
Subsequent LOS check determines the bypass vertices are out of LOS and the attack had no effect. Is the FL still valid and in
effect?
A. Yes.

Serves me right for calling it "uncontroversial" -- I should know better.