Patching apropos.el in the following manner seems to have fixed the problem.

(defun apropos-value-internal (predicate symbol function)

(if (funcall predicate symbol)

(progn

(setq symbol (or (ignore-errors

(prin1-to-string (funcall function symbol)))

""))

(if (string-match apropos-regexp symbol)

(progn

(if apropos-match-face

(put-text-property (match-beginning 0) (match-end 0)

'face apropos-match-face

symbol))

symbol)))))

Evgeni