questions counter incremented by 2 when AJAX is used

[peerlight]

Using normal mode the question counter in each question is incremented by 1 as it should be: Frage 5 von 17, Frage 6 von 17 ...

When AJAX is used the question counter is incremented by 2: Frage 1 von 17, Frage 3 von 17, Frage 5 von 17 ...

plugin.tx_fpmasterquiz.settings.showQuestionNo = 1
plugin.tx_fpmasterquiz.settings.pagebrowser.itemsPerPage = 1

fp_masterquiz 3.4.4 from TER
TYPO3 10.4.30
PHP 7.2.x

[peerlight]

called with
https://www.domain.de/index.php?tx_fpmasterquiz_pi1[__referrer][@extension]=FpMasterquiz&tx_fpmasterquiz_pi1[__referrer][@controller]=Quiz&tx_fpmasterquiz_pi1[__referrer][@action]=show&tx_fpmasterquiz_pi1[__referrer][arguments]=...&tx_fpmasterquiz_pi1[__referrer][@request]={"@extension":"FpMasterquiz","@controller":"Quiz","@action":"show"}d452e35937808ce903ad0becb89b6c29be9d1a66&tx_fpmasterquiz_pi1[__trustedProperties]={"action":1,"quiz":1,"uidOfCE":1,"startTime":1,"participant":1,"currentPage":1,"showAnswers":1,"useJoker":1,"quizGoOn":1}d6ee7a160fd1c22aaa61a2d383b0ef4beb11e8db&type=190675&L=0&id=316&tx_fpmasterquiz_pi1[action]=showAjax&tx_fpmasterquiz_pi1[quiz]=4&tx_fpmasterquiz_pi1[uidOfCE]=1606&tx_fpmasterquiz_pi1[startTime]=1661862150&tx_fpmasterquiz_pi1[participant]=310&tx_fpmasterquiz_pi1[currentPage]=5&tx_fpmasterquiz_pi1[showAnswers]=0&tx_fpmasterquiz_pi1[useJoker]=0&quest_24=1&answer_24=67&_=1661862153485

the answer is

... <p class="quiz-question-no">Frage <span id="quiz-questno">9</span> von 17</p> ...

[bihor]

Well, I have testet it with TYPO3 10.4.32 and it looks good:
https://www.wegedermilch.de/interaktiv/kuh-klima-quiz
This value is used in the Partial Question/Properties.html:
{pageiterator.cycle}

What other (TypoScript) settings do you have?