hello safety guy,
it could be a tri-color visual approach slope indicator: (TRCV)
quote jepp in introduction chapter:"tcrv is normally a single light unit located on the left side of the runway".
amber: above glide path
green: on glide path
red: below glide path
caution note added: "when the aircraft descends from green to red, the pilot may see a dark amber color during the transition from green to red".
another possibility is the "pulsating visual approach slope indicator
PLASI) but only with white & red lights, also located normally on left side of rwy.
pulsating white: abv glide path
steady white: on glide path
steady red: slightly below glide path
pulsating red: below glide path
caution note this time: "when viewing the pulsating visual approach slope indicators in the pulsating white or pulsating red sectors, it is possible to mistake this lighting aid for another aircraft or ground vehicle. pilots should exercise caution when using this system".
last remark: vasi/papi are certified only from about 4nm out cfr obstacles & if non-std coverage a caution note is usually added.
vasi is normally ok till 200ft agl.
papi is ok till 100ft agl.
and, yes, growing grass can obscure correct viewing of colors, as can hazy wx conditions(prisma effect).
the system can be off or on maintenance or even worse, not installed at all, see paris orly where no vasi/papi system exist on the main landing rwy's.
and safety guy, cfr some funny comments of some previous posts: don't worry, quote the bible as jesus was saying on mount golgotha: "forgive them, my lord, they do not know what they are doing".