Is this a grave mistake in DN22 translation?

This question is from MahāsatipatthānaSutta, so recite and memorize MahāsatipatthānaSutta uncountable times are the simplest way to get the answer. How can we trust in people we asking? Why don't we recite and memorize Pali and get the answer ourselves?

MahāsatipatthānaSutta KhandhaPabba:

Idha, bhikkhave, bhikkhu, ‘iti rūpaṃ, iti rūpassa samudayo, iti rūpassa atthaṅgamo; iti vedanā, iti vedanāya samudayo, iti vedanāya atthaṅgamo; iti saññā, iti saññāya samudayo, iti saññāya atthaṅgamo; iti saṅkhārā, iti saṅkhārānaṃ samudayo, iti saṅkhārānaṃ atthaṅgamo; iti viññāṇaṃ, iti viññāṇassa samudayo, iti viññāṇassa atthaṅgamo’ ti.

Here, bhikkhus, a bhikkhu [discerns]: "such is rūpa, such is the samudaya (arising and its' origins) of rūpa, such is the passing away (vanishing and its' origins) of rūpa; such is vedanā, such is the samudaya of vedanā, such is the passing away of vedanā; such is saññā, such is the samudaya of saññā, such is the passing away of saññā; such is saṅkhāra, such is the samudaya of saṅkhāra, such is the passing away of saṅkhāra; such is viññāṇa, such is the samudaya of viññāṇa, such is the passing away of viññāṇa".

Iti ajjhattaṃ vā dhammesu dhammānupassī viharati, bahiddhā vā dhammesu dhammānupassī viharati, ajjhatta-bahiddhā vā dhammesu dhammānupassī viharati; samudaya-dhamm·ānupassī vā dhammesu viharati, vaya-dhamm·ānupassī vā dhammesu viharati, samudaya-vaya-dhamm·ānupassī vā dhammesu viharati; ‘atthi dhammā’ ti vā pan·assa sati paccupaṭṭhitā hoti, yāvadeva ñāṇa·mattāya paṭissati·mattāya, a·nissito ca viharati, na ca kiñci loke upādiyati. Evam·pi kho, bhikkhave, bhikkhu dhammesu dhammānupassī viharati, pañcasu upādānakkhandhesu.

Thus he dwells observing dhammas in dhammas internally, or he dwells observing dhammas in dhammas externally, or he dwells observing dhammas in dhammas internally and externally; he dwells observing the samudaya of phenomena in dhammas, or he dwells observing the passing away of phenomena in dhammas, or he dwells observing the samudaya and passing away of phenomena in dhammas; or else, [realizing:] "these are dhammas!" sati is present in him, just to the extent of mere ñāṇa and mere paṭissati, he dwells detached, and does not cling to anything in the world. Thus, bhikkhus, a bhikkhu dwells observing dhammas in dhammas, with reference to the five khandhas.

Even assuming attha.m could be equated to attā, it could not mean "the not taking as self", because gama here means"the going", so it would mean something like "the going to self of pain and sadness".

Also atthaṅgama is a common enough word to leave very little doubt over its meaning:

“yato kho, bhikkhave, bhikkhu channaṃ phassāyatanānaṃ samudayañca atthaṅgamañca..."

"iti rūpassa samudayo, iti rūpassa atthaṅgamo..."

“santāvuso, sattā sabbaso rūpasaññānaṃ samatikkamā paṭighasaññānaṃ atthaṅgamā..."

"ye hi keci, bhikkhave, samaṇā vā brāhmaṇā vā imāsaṃ dvinnaṃ diṭṭhīnaṃ samudayañca atthaṅgamañca..."

“puna caparaṃ, brāhmaṇa, bhikkhu sukhassa ca pahānā dukkhassa ca pahānā pubbeva somanassadomanassānaṃ atthaṅgamā adukkhamasukhaṃ upekkhāsatipārisuddhiṃ catutthaṃ jhānaṃ upasampajja viharati."

"yo tassā nirodho vūpasamo atthaṅgamo..."

The entire PED section on Attha 2 is of interest:

Attha2 (nt.) [Vedic asta, of uncertain etym.] home, primarily as place of rest & shelter, but in P. phraseology abstracted from the "going home", i. e. setting of the sun, as disappearance going out of existence, annihilation, extinction Only in acc. and as ˚ -- in foll phrases: atthangacchati to disappear, to go out of existence, to vanish Dh 226 (= vināsaŋ natthibhāvaŋ gacchati DhA iii.324), 384 ( parikkhayaŋ gacchati); pp. atthangata gone home, gone to rest, gone, disappeared; of the sun (= set): J i.175 (atthangate suriye at sunset); PvA 55 (id.) 216 (anatthangate s. before sunset) fig. Sn 472 (atthagata). 475 (id.) 1075 (= niruddha ucchinṇa vinaṭṭha anupādi -- sesāya nibbāna -- dhātuyā nibbuta); It 58; Dhs 1038; Vbh 195 -- atthagatatta (nt. abstr.) disappearance SnA 409. -- atthangama (atthagama passim) annihilation, disappearance opposed to samudaya (coming into existence) and synonymous with nirodha (destruction) D i.34, 37, 183; S iv.327; A iii.326; Ps ii.4, 6, 39; Pug 52; Dhs 165 265, 501, 579; Vbh 105. -- atthagamana (nt.) setting (of the sun) J i.101 (suriyass' atthagamanā at sunset DA i.95 (= ogamana). -- attha -- gāmin, in phrase udayɔ atthagāmin leading to birth and death (of paññā): see udaya. -- atthaŋ paleti = atthangacchati (fig.) Sn 1074 (= atthangameti nirujjhati Nd2 28). -- Also atthamita (pp. of i) set (of the sun) in phrase anatthamite suriye before sunset (with anatthangamite as v. l. at both pass. DhA i.86; iii.127. -- Cp. also abbhattha.

So no, that part of their translations seems fine.