What numbers did you use? For example, I created the following code:
Code:
INSERT INTO StartBiasResources (CivilizationType, ResourceType, Tier)
VALUES ('CIVILIZATION_GERMANY', 'RESOURCE_STONE', '2');
INSERT INTO StartBiasRivers (CivilizationType, Tier)
VALUES ('CIVILIZATION_GERMANY', '2');
And so far, in all starts I generated, Germany started at a river with at least one stone resource nearby (sometimes 2 or even 3). I think you might have used higher numbers, which seems to translate to "less important".
But it might also be that resource or river bias is much more reliable than terrain. I've often seen Russia start on Plains or Grassland that was like one city distance away from Tundra, but they "only" have a value of 3. To be honest though, I haven't messed around much with terrain bias.