the flickering is still an issue. but i found what i think might be a few good clues. i hope i can create a failing test too.

the example is from the copenhagen area. moving the end point a few meters along the same way suddently makes osrm choose a rounte that's twice the lenghth, and also slower.

i copied the queries from the browser and sent them manually. the results are the same, and is what you see below. this shows that the problem is not with the GUI, but with osrm itself.

i will email you screenshots too.

start point:
http://www.openstreetmap.org/?mlat=55.681293413931&mlon=12.557324286979&zoom=17

end point 1:
http://www.openstreetmap.org/?mlat=55.679992884831&mlon=12.556337234039&zoom=17

with this end point, osrm correctly chooses to go clockwise around the block, which is 190m, mainly footpath (at 5km/h), and takes 79 seconds:

http://localhost:5000/viaroute&start=55.681293413931,12.557324286979&dest=55.679992884831,12.556337234039&z=18&output=json&jsonp=showResultsRoute&geomformat=cmp&instructions=true

showResultsRoute(
{"version": 0.3,"status":0,"status_message": "Found route between points","route_summary": {"total_distance":190,"total_time":79,"start_point":"Svineryggen","end_point":"Martinsvej"},"route_geometry": "agzrIcrskAnGfAIlBAJ","route_instructions": [["Head","Svineryggen",152,0,107,"152m","S",170.29],["Turn right","",34,1,179,"34m","E",81.99],["Continue","Martinsvej",3,2,37,"3m","E",75.53]],"via_points":[],"transactionId": "OSRM Routing Engine JSON Descriptor (v0.3)"})

end point 2:
http://www.openstreetmap.org/?mlat=55.679992884831&mlon=12.556358691732&zoom=17

moving the end point a few meters, osrm now incorrectly chooses to go counter-clockwise around the block, which is 400m, mainly residential road, and takes 88 seconds. it's both longer and slower than the first route.

http://localhost:5000/viaroute&start=55.681293413931,12.557324286979&dest=55.679992884831,12.556358691732&z=18&output=json&jsonp=showResultsRoute&geomformat=cmp&instructions=true

showResultsRoute(
{"version": 0.3,"status":0,"status_message": "Found route between points","route_summary": {"total_distance":400,"total_time":88,"start_point":"Svineryggen","end_point":"Martinsvej"},"route_geometry": "agzrIcrskAoB]JbCrFdGxAhAXwF","route_instructions": [["Head","Svineryggen",62,0,126,"62m","N",349.14],["Turn left","Rosenørns Alle",41,1,100,"41m","E",98],["Turn slight left","Vodroffsvej",213,2,512,"213m","SE",143.94],["Turn sharp left","Martinsvej",79,4,28,"79m","W",260.75]],"via_points":[],"transactionId": "OSRM Routing Engine JSON Descriptor (v0.3)"})

this is the speedprofile used:

[bicycle]
    accessTag       = bicycle
    defaultSpeed    = 17
    obeyOneways     = yes
    useRestrictions = yes
    obeyBollards    = no

    cycleway        = 15
    primary         = 15
    primary_link    = 15
    secondary       = 15
    secondary_link  = 15
    tertiary        = 15
    residential     = 15
    road            = 15
    unclassified    = 15
    living_street   = 13
    track           = 12
    service         = 10
    path            = 10
    footway         = 7
    pedestrian      = 5
    pier            = 5
    steps           = 3
    ferry           = 5

    excludeFromGrid = ferry