Programming error - cross fingers

[Andrew Bernard]

I am trying to write a crotchet chord with two notes each with a \flageolet on them (as per a recent thread).

In my score of a very densely packed 25 pages so far when doing this I get the following error, multiple times

programming error: Grob direction requested while calculation in progress.

continuing, cross fingers

and the second flageolet does not render.

While I am sure this is informative to some, since there is no position or context indicated, I am at a loss to know how to debug my score.

Using version 2.19.43.

I apologise if this question appears hopelessly vague. I am utterly unable to reproduce this behaviour in a standalone MWE.

The gist of this email is that I would appreciate it if anybody could tell me the sort of issues that this error is trying to alert one to.

Dare I suggest timidly that a line number or rough location or _something_ would be helpful with this error? As with similar errors before, crossing one’s fingers achieves nothing - and may better be omitted from such messages, or perhaps rephrased to something less witty (?) such as ‘making best effort to continue’ or similar.

Andrew