Vanishing cyclists

Around the city where I live there is an oddness to the cycle lanes.
From my car I see them there and then next minute the lane has disappeared.
What are the cyclists suppose to do at this point - start to fly?
It is always at odd points too. Like coming up to a particularly nasty intersection where you'd think cyclists would like a lane of their own to protect them. Or weirdly just after special signs alerting motorists to the existence of a cycle lane and after the cycle lane goes across in front of merging traffic. Then it's gone - right where the merging traffic will be appearing beside them.
Do the planners think cyclists can materialise or not at will?
If these lanes are suppose to make the cyclists safer - why do they disappear in the most unsafe spots?
If cyclists could fly - wouldn't they just do this all the time? It would be so much faster.
Maybe the streets are just one big computer game with cyclists as the players. When the cycle lanes suddenly stop they vanish and reappear on another cycle lane somewhere else. Maybe me and my car are merely obstacles passing through.