555 Timer Monostable Multivibrator (RC-Differentiated Trigger)

The circuit is a 555 timer configured as a monostable multivibrator with RC differentiator between the trigger source and the TRIGGER input of the timer. This circuit can be found in multitude of references such as books, magazines, technical manuals, web pages, etc. but I created this circuit because I have to cite this in some other circuits that I created. When the Clock Voltage source is at high state, the diode clamps the voltage at the TRIGGER pin to one diode drop above Vcc. If 1N4148 is used it does not work as expected. The voltage is instead limited to less than 2 V lower than 2Vcc, much higher than expected. The result is the same for National Semiconductor Model 1N4148_2 and NXP Semiconductors Models 1N4148_2 and 1N4148/NXP whether Initial conditions is set to "Determine automatically" or "User defined". Initial conditions is set to "User defined" to produce the correct result. If Initial conditions is set to "Determine automatically" there is a spike (voltage initially higher than Vcc then discharging towards it) on the trigger input at the start of simulation time. Setting the Rise time (TR) of the Clock Voltage source to 0 s does not eliminate that spike. This kind of spike should appear only on the second and subsequent rising edge of the input pulse train. It should not be on the first rising edge since the input signal starts at high state while the capacitor, initially, has no charge.