"412 Precondition failed"-upload-error when working with relations

[Schusch]

Working with relations, i often get a "412 Precondition failed"-error when uploading ... example (i haven't corrected it up to now, so you can see it (correction with potlatch is possible)):

B 9 ways 28223133, 28222964, 28507307 can't be added to relation 29891 (route B 9)

(see ​http://www.openstreetmap.org/?lat=49.54723&lon=8.39505&zoom=16&layers=B000FTFT)

i think my tries even deleted some of the ways from the relation - which was clearly not intended ...

[Schusch]

see also #1748

[anonymous]

now i realise another important point - this loosing the relation mistakes depends on splitting existing ways with relations ...

(i corrected the lost relations of the B 9 near motorway junction Ludwigshafen-Nord of A 6 with the help of potlatch some minutes ago)

[anonymous]

i can confirm this matter;

i try to delete a part of a double street segment which is part of a relation between the crossing of St.-Töniser-Str. along Frankenring antil corner of Am Westbahnhof;

​http://www.openstreetmap.org/?lat=51.330716&lon=6.548641&zoom=18&layers=B000FTF

but this always ends with the error message during uploading to server as above-mentioned

[anonymous]

Duplicate #1748