looper clicks randomly, clicks when clearing the buffer

Hi,

i tried to build a simple looper. no reverse or speedchange required.
It should be "half" quantized. that means that the start is free but the lenght is a multiple of 4n.

works so far.

but: it clicks. i tried fade in/outs and it's better at the borders now. but I still get random loud clicks (that are recorded) also in the middle of a cycle so I don't think this has anything to do with fades.

I'm not running a heavy set (only one synth), tried different audio buffers, CPU is about 22%.

I also get clicks when I clear the buffer. this happens until now in all patches that use a buffer. is there anything special to do with buffers?
it clicks also when I use the live looper and click on the loopers clear button.

any ideas?

this is the patch:

Thanks,
Karsten