TYPO3 Core

'displayCond' => 'FIELD:myfield:=:text:with:colons',

The operand is set to 'text' and not to 'text:with:colons', so the displayCond didn't work correct.

Bug in \TYPO3\CMS\Backend\Form\FormDataProvider\EvaluateDisplayConditions::parseSingleConditionString

Reason:
the $conditionArray uses trimExplode with no limit.

$conditionArray = GeneralUtility::trimExplode(':', $conditionString);

later in the code the operand is fetched from $conditionArray[3].

$operand = $conditionArray[3];