Which had begun running vs Which began running

Some examples from the web:

• Indeed, the euro area economy rebounded in 2006 after a prolonged period of subdued growth, which had begun in 2001.
• At the current time it is clear that we must express ourselves unambiguously against the way Raouf Denktash's attitude sabotaged the peace talks, which had begun optimistically.
• 1993 in particular was notable for a continuation of the turbulence in the Exchange Rate Mechanism of the EMS which had begun in the late summer of 1992.
• In May 1999 the company which was coordinating the work became insolvent and suspended performance of the project which had begun on 5 February 1999.
• The President referred to the first round of the presidential elections in Ukraine, which had taken place on 17 January 2010, and to the fact that the Spanish Presidency of the Council had begun.
• On 1 September 2016, Greece informed the Commission of the successful ending of the so called pre-registration exercise which had begun on 8 June 2016 [11].
• And this was before Wikipedia had begun, and this was developed by a 12-year-old, in his room, by himself, running on this tiny server using ancient technology.
• During the 19 th century the industrial revolution, which had begun in the United Kingdom at the end of the 18 th century with the introduction of the steam engine, gradually spread to most European countries, to the USA and to Japan.
• The recovery, which began in mid-1992, was principally associated with a turnaround in private consumption and was boosted by the reduction in interest rates, which had begun as early as 1990.
• Next day, sores had begun.
• Spielberg had begun shooting Schindler's List.
• He told you that the final countdown had begun.
• Amy had begun psychiatric treatment that was effectively recovering her past.
• Before production had begun Weinstein had given her his tentative approval.
• Olive wondered when her new beginning Would feel like it had begun.
• Tobias had begun work on the set of Scandal Makers.
• The owls had begun to circle around me.
• His war on Starling City's cancerous criminal elite had begun.
• Work had begun, in 1997, with a ground-breaking ceremony.
• A CIA analyst who had begun his own investigation into division joined me after I saved his life.

Some examples from the web:

• The temple began running an interference frequency.
• Now, if the killer began running immediately...
• Which began, ironically, in the very bed now occupied by her stricken father.
• It is a philosophy which began generations ago.
• Reporter: ... Which began with a raid in Nuevo Laredo yesterday evening.
• Cautious protests which began in marginalised regions developed into a countrywide uprising.
• This is not a bad record after a century which began so badly.
• You showed admirable and unyielding courage throughout your detention which began on 20 November 1992.
• Which began this bizarre cycle of violence two days ago.
• The development seen above resulted from the financial crisis which began around October 2008.
• The recovery in employment, which began in spring 1997, strengthened throughout 1998.
• This Regulation should provide for transitional measures to monitor actions which began before 31 December 2013 under Decision No 1904/2006/EC.
• Several of which began before she joined the firm.
• Producers are in debt and cannot get over the crisis which began in 1992.
• The hunger strike in Greek prisons, which began on 3 November 2008, is continuing.
• The avian influenza which began towards the end of 2003 in Southeast Asia affected over 150 million birds.
• Work which began on 22 June 2005 was interrupted following a complaint for damages made by a person living nearby.
• The ways of the rich and all my longing, which began that day.
• The example of Brazil, which began free treatment of all AIDS victims in 1996, speaks volumes.
• This situation has had a genuinely tortuous history, which began last summer.