Traditional realism typically holds that there is a division between the inner mental life of a subject and the reality outside of mental representation had by that subject. Epistemologically there are concepts and then the objects which those concepts are about. Inside and outside, subject and object, concept and object to which a concept refers.
Phenomenology effaces the division between inside and outside, internal and external, concept and object, by saying that objects and concepts are equally as real in any given conscious appearance, indeed in appearance objects are as they appear. Appearance is the "givenness" of phenomena external to the mind within human experience; that is, within human consciousness. Phenomenology focuses on describing how or in what way phenomena appear. The division between inside and outside is collapsed, although collapsed "in" upon the side of the subject given that content of description is the layer of human experience that is the "external" objects appearing to the subject describing it.
The trouble seems to be that, ontologically, in order to be a thoroughgoing realist, one should say that these objects do not depend upon human experience or the "consciousness of" things in order to have the character that they do (and by this I mean "to have a character" means to be presented in some way. Thus a subject seems required to bring about the qualities that are described as they are described). A realist would like to say that reality is quite independent of and autonomous of human experience and its manner of apprehension, as passive as that manner may be (and so the phenomenological realist would defer to the reality of how things appear having bracketed theoretical presuppositions about that appearance). The trouble occurs in that phenomenology claims it is not a problem to state that things are simply as they are given to human consciousness as there is a certain trust in the manner of the appearance.
Husserlian phenomenology emphasizes the transcendental and "lived" qualitative immediacy of the appearance. His transcendental version of phenomenology requires that these appearances be divested to a reflective consciousness always already within a "life-world." Thus there is always a certain "being conditioned-ness" that the human observer always brings to the table which challenges the overall "autonomy" of reality component present in the independence of its presentation. In other words, the independence of what things are in their own autonomous nature appears to be challenged by the requirement of phenomenal presentation needed for phenomenology's "realist" descriptions.
Other phenomenologies do not emphasize these same Husserlian moments however, and so the same challenge to the autonomy of the real is not present. Instead, these phenomenologists shift attention to the becoming of the real itself - its activity rendered phenomenologically not strictly in qualitative terms presented to human consciousness but in terms of categorial-modal becoming. The key is that these categorial or modal descriptions are broad enough so as to encompass qualitative description as much as they are metaphysical (realist) description in other terms. The point is to elide conscious description and enter into not sensible appearance but the presentation of sensibility itself.
For example, the "ordinal" phenomenology of the obscure American philosopher Justus Buchler states that reality is whatever is in whatever way it is (the ontological claim of phenomenology) yet it does not rely on privileging the mere appearance of whatever appears. The natural complexity of reality is focus rather than that complexity's so-called conscious apprehension.
Hartshorne's (and Whitehead's) process phenomenology emphasizes the powers of what phenomenology attempts to explicate, however not in terms of descriptive reportage but in terms of aesthetic feeling through "prehension," better rendered in art, literature, or poetry than in any "description of essences."
And Peirce's phenomenology seems to shift focus back to the categorical exhibitive display of the real itself, attending first and foremost not to a mere human description at all but to an a priori categorical and metaphysical disclosure of a pre-objective indivision, a "first nature" (erst Natur) which is essentially cosmological as it is phenomenological, for it is the "ground" of any conscious presentation whatsoever. For Peirce, "Firstness" is "first Nature." The un-prethinkable.