In Jainism, “Duṣamā–Suṣamā” and “Suṣamā–Duṣamā” (often loosely said as “Dushma Sushma”) are two of the six eras (ārā / kāl) of the time‑cycle (Kāl‑chakra).

Six eras in each half of time

Every half cycle of time (both Utsarpini – ascending and Avasarpini – descending) has these six aras:

1. Suṣamā‑Suṣamā – only happiness
2. Suṣamā – happiness (slightly less)
3. Suṣamā‑Duṣamā – more happiness, little sorrow
4. Duṣamā‑Suṣamā – more sorrow, some happiness
5. Duṣamā – mostly sorrow
6. Duṣamā‑Duṣamā – almost only sorrow

So the “mixed” eras you are asking about are:

• Suṣamā‑Duṣamā (3rd) – world still mostly happy, but sorrow has clearly started.
• Duṣamā‑Suṣamā (4th) – sorrow is more, but some happiness is still there.

Our current era

According to Jain tradition, in Bhārat Kṣetra we are now in:

• 5th era – Duṣamā (Dukhma Kāl) of the Avasarpini (descending) half‑cycle.
• After this will come the 6th era – Duṣamā‑Duṣamā, which is even more sorrow‑dominant.

Both Digambar and Shvetambar accept:

• The same six‑era structure,
• The names and the general meaning,
• That we are presently in the 5th era (Duṣamā) of Avasarpini.

Only some detailed calculations of years differ.

You can read a simple explanation of the six kāls and our present era here