https://vedicfeed.com/shukracharya-the-guru-of-asuras/
Rishi Bhrigu, the father of Shukracharya and the husband of Kavyamata, curses Vishnu saying,“ Hey Vishnu! By killing a woman, you have breached Dharma and I, hereby, curse you to take seven births as a Human”. (However, later, Rishi Bhrigu breathes life into his wife Kavyamata.)
So it is written in this article.
I know that aavatars are not humans.
So who are supposed to be those humans?
Can Rishis curse Gods?
Lord Vishnu respects the words of the Brahmarishis such as Bhrigu and never lets them go in vain.
Bhrigu repents after having spoken the curse and Lord Vishnu reassures him.
Having pronounced this curse, Bhrigu was overcome with remorse and his merits being exhausted by the malediction he had uttered, he began to propitiate that God, paying homage to the One who delights in penance and protects his devotees. Thereafter Lord Vishnu spoke, saying, “For the good of the worlds, I will be subject to your curse." (Valmiki Ramayana Uttara Khanda Chapter 51).”
To further corroborate this, here's another incident from Bhagavata Purana Canto 10 where Bhrigu kicks Vishnu's divine chest but later cries in repentance after hearing Lord Vishnu's words of humility.
शयानं श्रिय उत्सङ्गे पदा वक्षस्यताडयत् । तत उत्थाय भगवान् सह लक्ष्म्या सतां गति: ॥ ८ ॥ स्वतल्पादवरुह्याथ ननाम शिरसा मुनिम् । आह ते स्वागतं ब्रह्मन् निषीदात्रासने क्षणम् । अजानतामागतान् व: क्षन्तुमर्हथ न: प्रभो ॥ ९ ॥
There he went up to the Supreme Lord, who was lying with His head on the lap of His consort, Śrī, and kicked Him on the chest. The Lord then rose, along with Goddess Lakṣmī, as a sign of respect. Coming down from His bedstead, that supreme goal of all pure devotees bowed His head to the floor before the sage and told him, ‘Welcome, brāhmaṇa. Please sit in this chair and rest awhile. Kindly forgive us, dear master, for not noticing your arrival.’
पुनीहि सहलोकं मां लोकपालांश्च मद्गतान् । पादोदकेन भवतस्तीर्थानां तीर्थकारिणा ॥ १० ॥ अद्याहं भगवँल्लक्ष्म्या आसमेकान्तभाजनम् । वत्स्यत्युरसि मे भूतिर्भवत्पादहतांहस: ॥ ११ ॥
“Please purify Me, My realm and the realms of the universal rulers devoted to Me by giving us the water that has washed your feet. This holy water is indeed what makes all places of pilgrimage sacred. Today, my lord, I have become the exclusive shelter of the goddess of fortune, Lakṣmī; she will consent to reside on My chest because your foot has rid it of sins.”
श्रीशुक उवाच एवं ब्रुवाणे वैकुण्ठे भृगुस्तन्मन्द्रया गिरा । निर्वृतस्तर्पितस्तूष्णीं भक्त्युत्कण्ठोऽश्रुलोचन: ॥ १२ ॥
Śukadeva Gosvāmī said: Bhṛgu felt satisfied and delighted to hear the solemn words spoken by Lord Vaikuṇṭha. Overwhelmed with devotional ecstasy, he remained silent, his eyes brimming with tears.
Purport: Bhṛgu could not offer the Lord any words of praise because his throat was choking with tears of ecstasy. In the opinion of Śrīla Viśvanātha Cakravartī, the sage should not be condemned for his offensive behavior, since his role in this transcendental pastime was arranged by the Personality of Godhead.
पुनश्च सत्रमाव्रज्य मुनीनां ब्रह्मवादिनाम् । स्वानुभूतमशेषेण राजन् भृगुरवर्णयत् ॥ १३ ॥
O King, Bhṛgu then returned to the sacrificial arena of the wise Vedic authorities and described his entire experience to them.
Thus, great Rishis such as Bhrigu are utilized by the Lord as an instrument to enact His Leelas.
