notes on the Dhamma: error in pali source, AN 9.41 fourth jhana impurity is sukha, not upekkha

pali source is cst4.

and BJT pali source has same error:
4. So kho ahaṃ ānanda aparena samayena sukhassa ca pahānā dukkhassa ca pahānā pubbeva somanassadomanassānaṃ atthaṅgamā adukkhamasukhaṃ upekkhāsatipārisuddhiṃ catutthaṃ jhānaṃ upasampajja viharāmi. Tassa mayhaṃ ānanda iminā vihārena viharato upekkhāsahagatā saññāmanasikārā samudācaranti. Svāssa me hoti ābādho. Seyyathāpi ānanda sukhino dukkhaṃ upapajjeyya yāvadeva ābādhāya, evamevassa me upekkhāsahagatā saññāmanasikārā samudācaranti, svāssa me hoti ābādho.

The error is on two levels.

On the doctrinal level,

AN 9.41 doesn't match SN 40.4
which has the correct impurity popping up in 4th jhana, sukha.

SN 40.4:

So khvāhaṃ, āvuso, sukhassa ca pahānā dukkhassa ca pahānā pubbeva somanassadomanassānaṃ atthaṅgamā adukkhamasukhaṃ upekkhāsatipārisuddhiṃ catutthaṃ jhānaṃ upasampajja viharāmi.	And so … I was entering and remaining in the fourth jhāna.
Tassa mayhaṃ, āvuso, iminā vihārena viharato sukhasahagatā saññāmanasikārā samudācaranti.	While I was in that meditation, perceptions and attentions accompanied by pleasure beset me.

AN 9.41 wrongly has

Tassa mayhaṃ, ānanda, iminā vihārena viharato upekkhāsahagatā saññāmanasikārā samudācaranti. Svassa me hoti ābādho.	While I was in that meditation, perceptions and attentions accompanied by equanimous pleasure beset me, and that was an affliction for me.
Seyyathāpi, ānanda, sukhino dukkhaṃ uppajjeyya yāvadeva ābādhāya;	Suppose a happy person were to experience pain; that would be an affliction for them.
evamevassa me upekkhāsahagatā saññāmanasikārā samudācaranti. Svassa me hoti ābādho.	In the same way, when perceptions and attentions accompanied by equanimous pleasure beset me, that was an affliction for me.

From STED 3rd jhana formula we know 'sukham ca kayena pati-samvedeti' is pleasure experienced with the physical body. upekkha is present in both 4th and 3rd jhana, so it can not be an impure element that intrudes upon 4th jhana. Whatever 'upekkhā-sukhe' is supposed to be, it doesn't make any sense and doesn't match the physical sukha/pleasure of 3rd jhana.

Error on sloppy editing level

The equanimous pleasure referred to, in the previous paragraph of AN 9.41 is:

Tasmā me adukkhamasukhe cittaṃ na pakkhandati nappasīdati na santiṭṭhati na vimuccati etaṃ santanti passato’.	That’s why my mind isn’t eager to be without pleasure and pain, and not confident, settled, and decided about it. And it’s why I don’t see it as peaceful.’
Tassa mayhaṃ, ānanda, etadahosi:	Then I thought:
‘sace kho ahaṃ upekkhāsukhe ādīnavaṃ disvā taṃ bahulaṃ kareyyaṃ, adukkhamasukhe ānisaṃsaṃ adhigamma tamāseveyyaṃ, ṭhānaṃ kho panetaṃ vijjati yaṃ me adukkhamasukhe cittaṃ pakkhandeyya pasīdeyya santiṭṭheyya vimucceyya etaṃ santanti passato’.	‘Suppose that, seeing the drawbacks of equanimous pleasure, I was to cultivate that. And suppose that, realizing the benefits of being without pleasure and pain, I was to develop that. It’s possible that my mind would be eager to be without pleasure and pain; it would be confident, settled, and decided about it. And I would see it as peaceful.’
So kho ahaṃ, ānanda, aparena samayena upekkhāsukhe ādīnavaṃ disvā taṃ bahulamakāsiṃ adukkhamasukhe ānisaṃsaṃ adhigamma tamāseviṃ.	And so, after some time, I saw the drawbacks of equanimous pleasure and cultivated that, and I realized the benefits of being without pleasure and pain and developed that.
Tassa mayhaṃ, ānanda, adukkhamasukhe cittaṃ pakkhandati pasīdati santiṭṭhati vimuccati etaṃ santanti passato.	Then my mind was eager to be without pleasure and pain; it was confident, settled, and decided about it. I saw it as peaceful.