Another complete misunderstanding:

Some devotees claim that raganuga-sadhana-bhakti starts at the stage Srila Rupa Goswami called and described as NISTHA.
They base their “claim” on their understanding of the following verse from Srila Rupa Goswamipada’s Bhakti Rasamrita Sindhu:

tatra adhikārī— rāgātmikāika-niṣṭhā ye vraja-vāsi-janādayaḥ | 
teṣāṁ bhāvāptaye lubdho bhaved atrādhikāravān 
||1.2.291|| 

Translation by HH Bhanu Swami [ISKCON]:

The qualification for rāgānuga-bhakti is as follows:

That person who is greedy for attaining a bhāva similar to that of the inhabitants of Vraja—who are fixed solely in rāgātmika-bhakti—is qualified for rāgānuga-bhakti.  

Viśvanātha Cakravartī Ṭhākura’s Commentary

Having described the characteristics of rāgātmika-bhakti of the siddha-bhaktas, the author now describes the characteristics of rāgānuga-bhakti of the sādhakas. He who is greedy to attain a bhāva similar to that of the people of Vraja—who are fixed in rāgātmika-bhakti [rāgātmikāika-niṣṭhā ] — is qualified for rāgānuga-bhakti.    

Quite honestly, I find THEIR translation of this verse quite wrong and misleading:

Qualification for raganuga sadhana bhakti:
That person who is greedy for attaining a bhava similar to that of inhabitants of vraja – who is at nishtha in ragatmika bhakti – is qualified for raganuga bhakti.

Where does either acarya write that raganuga-sadhana-bhakti starts at the STAGE “nistha”? Actually, this verse describes a very important impetus in raganuga bhakti: greed for attaining a bhava similar to the ragatmika devotees [who are fixed in their bhava].
And again, the biggest blunder:

“who is at nishtha in ragatmika bhakti”

So, the sadhaka, who is “at nistha in RAGATMIKA bhakti, is qualified for raganuga bhakti”…really?
First of all, RAGATMIKA refers to the nitya siddhas in Vraja, like Sri Rupa Manjari, Sri Ananga Manjari, Mother Yashoda, etc…and RAGANUGA refers to those WHO FOLLOW the RAGATMIKAS…
So, it is not US who are “at nistha in ragatmika bhakti”.

Yes, here in this verse, we can find the word “nistha”. But it doesn’t refer to the stage of NISTHA the SADHAKA must pass through.
It refers to the RAGATMIKA DEVOTEES, our eternal role models, like for example Sri Rupa Manjari. It means THEIR fixation, not the sadhaka’s. Here, it just means “fixation, eternal steadiness” in regards to the bhava of the ragatmika devotees. “Nistha” here is the adjective to the noun “ragatmika”.

It certainly does not mean that raganuga-sadhana-bhakti starts at the stage “nistha”.

Let Srila Vishvanatha Cakravartipad set things straight:

Now it will be described how the raganugiya bhakta gradually advances through the stages of anartha nivritti (cessation of bad habits), nishtha (fixation), ruci (taste), and asakti (attachment to the beloved deity) upto the stage of prema (love of God) and the direct attainment of his beloved deity. 
(Raga Vartma Chandrika)

Clearly, raganuga-sadhana-bhakti starts at BHAJANA KRIYA and then the sadhaka “advances through the stages of…….”.

It starts when Sri Gurudeva engages the sadhaka in raganuga-sadhana-bhakti and the only cause for the sadhaka being able to start it is the mercy of Krishna and His devotees.

krsna-tad-bhakta-karunya-matra-labhaika-hetuka
pusti-margataya kaiscid iyam raganugocyate
|| BRS 1.2.309 ||

“The mercy of Krsna and His devotees is the only cause of attaining raganuga-bhakti. Some call this type of devotion pusti-marga.”

And by the way, the sadhaka develops this sacred greed by hearing from the lips of rasika sadhus describing the bhavas of the above mentioned ragatmikas as Srila Rupa Goswamipad will explain in later verses.

Let us see what our acaryas say about RAGATMIKA:

virājantīm abhivyaktāṁ vraja-vāsī janādiṣu |
rāgātmikām anusṛtā yā sā rāgānugocyate ||
[BRS 1.2.270]

Rāgānuga-bhakti is defined as that bhakti which follows after the rāgāmika-bhakti found distinctively in the inhabitants of Vraja.

Viśvanātha Cakravartī Ṭhākura’s Commentary

That is called rāgānuga-bhakti which follows after the rāgātmika-bhakti which manifests (virājantīm) distinctively (abhivyaktām) in the inhabitants of Vraja.

rāgātmikāyā dvaividhyād dvidhā rāgānugā ca sā |
kāmānugā ca sambandhānugā ceti nigadyate ||
[BRS 1.2.290]

From these two types of rāgātmika-bhakti (siddha-bhakti), two types of rāgānuga-bhakti (sādhana-bhakti), called kāmānuga and sambandhānuga-bhakti, are derived.

Viśvanātha Cakravartī Ṭhākura’s Commentary

Having described the qualities of rāgātmika-bhakti as a secondary topic, the qualities of rāgānuga-sādhana, the topic of this section, are now described.

Crystal.

Ragatmika bhakti => siddha [perfect] bhakti
Raganuga bhakti => sadhana [practice] bhakti.