Nope, wasn't it. But as I was putzing around trying other stuff I noticed a few attempts were within 2 seconds, but for no apparent reason. For some reason it appeared to be an unstable setup and I remembered that unset pins can do this. And that's when I remembered this from page 235 of the 18F4550:

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The pins of the Enhanced USART are multiplexed with
PORTC. In order to configure RC6/TX/CK and
RC7/RX/DT/SDO as a USART:
• bit SPEN (RCSTA<7>) must be set (= 1)
• bit TRISC<7> must be set (= 1)
• bit TRISC<6> must be cleared (= 0) for
Asynchronous and Synchronous Master modes
or set (= 1) for Synchronous Slave mode
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I had ignored this paragraph 'cause I had never seen a need for these resistors, I thought it was only for the Enhanced USART. So I added the 4K7 resistors on TX (pulldown) and RX (pullup) and everything works fine, even with my old code.

Thanks D!

Robert