ANZ Bank's share price was pummelled on Monday after the company warned investors that a big software write-off and mounting costs of customer remediation programs would wipe A$711 million from the 2018 second half profit.In a statement to the ASX, the bank revealed it incurred $374 million of special charges in the September half to compensate customers for a range of "issues", including inappropriate financial advice and 'fee for no service' cases.Most of the customer remediation bill relates to service breaches within the bank's continuing operations, with $127 million flowing from wealth businesses that were spun out of the group in the last 12 months.ANZ has also accelerated the amortisation of software used in its international banking operations, which will clip another $206 million from second half earnings.The bank has also booked further special charges in the second half of $131 million to cover legal bills stemming from the Hayne royal commission and to cover its internal reorganisation along Agile principles.Investors responded savagely to the disclosure, compounding the company's share price losses on a bleak day for banking stocks.ANZ was the worst performed listed bank stock for the day, closing down 2.63 per cent to $26.99.The profit warning triggered a wave of earnings downgrades by analysts, who said they were a tad surprised the bank had decided to absorb a large chunk of its remediation programs in the second half of 2018.The earnings hit triggered speculation that ANZ may be forced to rein in its share buyback activities, given that its Tier One capital position will take a take a hit of up to ten basis points because of the bottom line erosion.However, Goldman Sachs analyst Andrew Lyons believes the share buyback program should not be affected by the latest announcement because the bank is sitting on a lot more surplus capital than its peers.The profit warning caused Lyons to lower his earnings per share forecast by 7.8 per cent for the soon-to-be-announced 2018 full year result.Remediation challenges are expected to persist for several years, which inspired some analysts to also downgrade their 2019 and 2020 forecasts.Lyons, however, remains upbeat about ANZ's prospects relative to its peers and is retaining a "buy" recommendation on the stock."ANZ remains our preferred major bank exposure, given our view that it is best positioned to face into the slowing bank revenue environment, reflecting our expectation of further cost declines, a lower bad debt charge…and a reduction in share count as ANZ deploys surplus capital via buybacks," he told clients in a research report.ANZ chief executive Shayne Elliott is expected to unveil the group's annual results on 31 October.