Transmission interrupts, restarting solves it

I am still trying to solve my sometimes unstable operation . At some hours on the day the FT8 transmission is interrupted for short time. First idea was that the wifi channel is heavy loaded, but the problem seems to appear in cases where the channel is not that busy. Here a short movie showhing the waterfall during transmission.
waterfall
In most cases I can solve the problem by restarting wfview. So I am wondering whether there might be some bug in wfview e.g lack of memory or someghing else.

I am using a ic-705, wfview 1.2d, Macbook, connected by wifi. The sample rate: 8000, RX/TX latency 200ms

73 Peter DL5DLA