As referred to within your link (by the same author for sure), “A Flicker-Free Single-Stage Offline LED Driver With High Power Factor” article is through IEEE Membership to be purchased for $14.95 (I am not a member but may try to get one if requested).
Here is abstract: “A conventional offline single-stage light-emitting diode (LED) driver with a high power factor usually produces a significant twice-line-frequency ripple LED current, where the ripple LED current is presented as flickering to human eye. This paper introduces a ripple cancellation method to remove the twice-line-frequency voltage ripple for an offline single-stage LED driver with a power factor correction. Consequently, a DC LED current can be produced to achieve flicker-free LED driving performance.”
In future BOM selection this should help with issues like this one: