Hi Roland. The cross filter long is the highly efficiant cross filter, but the crossfilter short was made more as an option to fill in the gap of latency created in the cross filter long. As such it was never intended to have long times and is not made for multiple processor operation. In the default state (mono) the time is set to 0.069 s which for some re is too long where 0.05 s works OK. May be optimisation has altered the actual maximum time, not sure.
But if you want the zero latency that the crossfilter short gives you, you can use it in conjuntion with the crossfilter long to get a zero latency cross filter long. The latency of the long is exactly 1024 samples or 2048 if you select "AllowLongerCapture". So to make a zero latency long version, you need to mix the outputs of a long and a short crossfilter and feed then both with the same responce and signal. Set the shorts ResponceDuration to 1024 or 2048 samp, and to match it you need to offset the responce in the long by 1024 or 2048 samp. You do this by making the responce start of the crossfilter long to equal 1024 or 2048 samples late. Do this by setting the start field to 1024 samp /(captureduration s samp), or the 2048 eqivilant. The long will settle on the nearest 1024 or 2048 border as start and end control only change by those steps.
Also make sure the long and short have the same level and stereo mono state. You can still move the end time live but if you want to move ths start time , you have to give up zero latency and use the long on it's own.
I hope this makes sense.