rtc.readnvram(0) hangs on IDE version 2.3.2 but not on 1.8.7

[FlFlyer2024]

Using a DS1307 chip.
Compiling RTCLib version 1.10.0 under Arduino 1.8.7 works.
Compiling RTCLib version 2.1.4 under Arduino 2.3.2 the program hangs on rtc.readnvram(0); after re-power up:

RTC_DS1307 rtc;
int SpotlightLRpos;

setup()
...
SpotlightUDpos = rtc.readnvram(0);
...

I've tried changing the definition to
uint8_t SpotlightLRpos;
but still hangs, sometimes immediately after upload, sometimes after power off-on.

I should mention that use of the clock functions work just fine, so it appears that the I2C communication is not the problem.
Example:
DateTime now = rtc.now();