Visible Hexes/LOS

[Bacillus98]

Hello. I was trying to figure out how exactly LOS/visible hex system works in PzC. The manual really only talks about LOS in a couple of sentences that state "Seeing the target is based on the combined effect of Line-of-Sight and Visibility range. Basically, units cannot see through towns, woods or over hills, nor see beyond the maximum visibility for the environmental conditions." My wily PBEM opponent was able to use indirect fire on a Soviet unit in a forest hex 3 hexes away. According to the visible hexes view, there are five German units that can be a "possible" spotter. Visibility is exactly three hexes away from the spotting unit on this current turn due to weather. In all cases, the Germans units have this describing the 3 hexes to my unit. First hex is visible, second hex is greyed out, but the third hex where my unit is located(in a forest nevertheless) is normal, or visible. I thought a grey hex interrupts view of a unit. Any ideas on how my unit was spotted? Note: the German units are across a river so I don't see how a recon element comes into play.