I have created a schematic, see the attached screenshot. Now I am trying to simulate how it works in a digital SPICE simulator (built-in DipTrace 5.0 beta).
In general, it works almost reasonably. But there are strange signal distortions on some outputs of U3 on each falling edge of the clock coming to the input of decade counter U5. I have shown the problem with red marks.
What I am doing wrong? Is it a simulator issue or the schematic is incorrect?