Make sure your input or output pins meet the data sheet recommendations. For example:

• Data rate frequency.
• Load capacitance.
• Recommended to keep trace lengths and loading as minimal as possible. Note, connectors add to the lumped capacitive loading.
• Double check proper voltage levels for inputs (follow the device-specific VIH / VIL specification in the data sheet). Devices are over-voltage tolerant and inputs can be ≥ V_CC within the data sheet's recommended operating conditions.
• Series resistors used should be sufficient with the device's output impedance and transmission line used. For more information, see [FAQ] Can I estimate appropriate dampening resistor value for level-shifter outputs?
• Not recommended to have delay (RC) circuitry tied to input pins to avoid violating the data sheet's input transition spec. Violations can result to shoot-through currents and oscillations. For more information, see section 3 of Do's and Don'ts for TXB and TXS Voltage Level-Shifters with Edge Rate Accelerators, application note and Implications of Slow or Floating CMOS inputs.