Party mouthpiece 'Veekashanam', Malayalam daily, in a hard hitting editorial said Mani's politics was always that of "business, not righteous and unethical".
However, in a damage control exercise, KPCC President MM Hassan came out with a clarification that the views in the editorial was not that of the Congress and the party expressed apology for publishing the editorial.
'Veekshanam' came out with the article in the wake of an editorial in KC(M)'s mouthpiece that the party chief K M Mani had an offer of "Chief Ministership" from the then CPI(M)-led LDF opposition, but saved the previous UDF government not accepting the offer.
In an article in KC-M mouthpiece "Pratichaya", the party, which severed ties with UDF following bar bribery allegations against Mani after assembly elections last year, said history would have been something different had he then accepted the offer made by the LDF.
The 84-year-old Mani, who was the Finance Minister in the previous UDF regime, had to resign from the cabinet led by Oommen Chandy in the wake of bar bribery allegations, that led to friction in the three decades old relation between KC-M and Congress.
KC-M had also stated that bar bribery case was a "deliberate attempt" by a section in the Congress to clip the wings of the party, which had a large following in the Central Travancore region especially among Christians.
The relation between KC-M and Congress further worsened after UDF lost the state assembly polls resulting in KC-M snapping its ties with UDF in November 2015.
KC-M with six MLAs decided to sit as a separate block in the assembly.
"Mani's political immorality was clearly exposed with admission by the party that it had held talks with LDF while in UDF", the 'Veekashanam' editorial said.
It also said Mani had only tried to promote his son Jose K Mani, MP, in the party.
The editorial ended with an appeal to Congress that the party should not be ready to call Mani back to UDF fold for an another political reunity even if UDF gets defeated in polls hundred times.
Hassan in a statement said that views in the editorial was not that of the Congress and the party expressed apology for publishing the editorial.
It was a unilateral decision of KC-M to leave UDF, Hassan said.
KPCC had only expressed dissatisfaction and protest over KC-M for the deceitful stand taken during the Kottayam District Panchayat polls, Hassan said.
Though KC-M had snapped ties with UDF, the party had maintained its political arrangements in the civic bodies in the state.
During a recent election to Kottayam District Panchayat President, KC-M captured the post by unseating a Congress nominee with the support of CPI-M members.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)