Blink and AM use a sort of terrain-mapping function to determine a path, rather than just pinging the target. It's the terrain inconsistencies which cause the failure of the spell, coupled with latency issues... We've wanted to implement new methods of testing, such as putting 'artificial load' on a test environment, but that can be costly. We're also looking into other possibilities of 'live testing' so that latency can be taken into account, somewhat... The biggest problem with resolving these bugs has been recreating the variable of network latency, which affects these spells more than other types.