The IN+ and IN- inputs on the TS4231 are sensitive nodes that connect to a high-gain signal path. When attaching oscilloscope probes near the TS4231 on the D and E outputs sometimes you will see extra pulses on the D output. These pulses should not exist but they are often due to noise coupling through the scope probe to the TS4231 input. Scope probes add parasitics and create noise coupling loops.
Pulses on the D output of the TS4231 are valid only when the E output is also asserted. Pulses on the D output can be ignored when E is not asserted.
Performance will be much improved without scope probes connected to the output of the TS4231. This complicates debugging but TS4231 digital outputs can be monitored downstream via SteamVR HDK tools or in custom hardware within your custom FPGA or microprocessor code.
If you must probe near the TS4231, we recommend using an active differential probe or soldering a 30-gauge wire to the probe point and twisting with ground wire to minimize the probe loop area.